diff --git a/assignments/assignment_3.md b/assignments/assignment_3.md
index 0879663..4546220 100644
--- a/assignments/assignment_3.md
+++ b/assignments/assignment_3.md
@@ -12,3 +12,11 @@
 
 
 3. Deploy both `CounterV2` and `CounterV3` contracts and provide their corresponding following class_hash and contract addresses in a `solutions_3.md` file under the `Solutions` folder
+
+# CounterV2
+## 0x3ec3b11893ead66e0981f280d4a09303c9b8d2b51e7f92836a1c0a2e2b8b9c7
+## 0x2adfce772d97618bf8871bff3e8c0766147886da505a09dc3ce77777d52f398    -   https://sepolia.starkscan.co/class/0xfae52025fdff77f2ab38dd5eaa9a23540fbf7131e896d8b5699e2642944e33
+
+# CounterV3
+## 0xfae52025fdff77f2ab38dd5eaa9a23540fbf7131e896d8b5699e2642944e33
+## 0x1fa34f58aa881cb66e01a2156adca02e948a44351072d20d7d381783447bc2e    -   https://sepolia.starkscan.co/contract/0x1fa34f58aa881cb66e01a2156adca02e948a44351072d20d7d381783447bc2e
\ No newline at end of file
diff --git a/snfoundry.toml b/snfoundry.toml
index 336b432..baf7d20 100644
--- a/snfoundry.toml
+++ b/snfoundry.toml
@@ -1,10 +1,10 @@
-[sncast.cohort_dev]
-account = "cohort_dev"
+[sncast.anonfedora]
+account = "anonfedora"
 accounts-file = "~/.starknet_accounts/starknet_open_zeppelin_accounts.json"
 url = "https://free-rpc.nethermind.io/sepolia-juno/"
 
 
-[sncast.deploy_dev]
-account = "deploy_dev"
+[sncast.cohort_dev]
+account = "cohort_dev"
 accounts-file = "~/.starknet_accounts/starknet_open_zeppelin_accounts.json"
 url = "https://free-rpc.nethermind.io/sepolia-juno/"
\ No newline at end of file
diff --git a/src/counter_v2.cairo b/src/counter_v2.cairo
index 0cf84b9..a7d9b62 100644
--- a/src/counter_v2.cairo
+++ b/src/counter_v2.cairo
@@ -19,6 +19,9 @@ trait ICounterV2<TContractState> {
     // increase count by one
     fn increase_count_by_one(ref self: TContractState);
 
+    // decrease count by one
+    fn decrease_count_by_one(ref self: TContractState);
+
 
     fn get_current_owner(self: @TContractState) -> ContractAddress;
 }
@@ -72,6 +75,11 @@ mod CounterV2 {
             self.count.write(current_count + 1)
         }
 
+        // decrease count by one
+        fn decrease_count_by_one(ref self: ContractState) {
+            self.count.write(self.get_count() - 1)
+        }
+
         // util function to get current owner
         fn get_current_owner(self: @ContractState) -> ContractAddress {
             self.owner.read()
@@ -100,8 +108,8 @@ mod CounterV2 {
         }
     }
 }
-// 0x65f0904d094297f08575291f2da8600b60c12e764b63fdfef8c1044a3eaa34b
-// 0x6f2f6eb269f9741d5bb9cb633bfb632a0d71e0622b195ef4c4e66e8f1fee9fe
+// 0x3ec3b11893ead66e0981f280d4a09303c9b8d2b51e7f92836a1c0a2e2b8b9c7
+// 0x2adfce772d97618bf8871bff3e8c0766147886da505a09dc3ce77777d52f398
 // 0x000000000000000000000000000000000000000000000000000000000000000
 
 
diff --git a/src/counter_v3.cairo b/src/counter_v3.cairo
new file mode 100644
index 0000000..682cb4e
--- /dev/null
+++ b/src/counter_v3.cairo
@@ -0,0 +1,99 @@
+use starknet::ContractAddress;
+
+#[starknet::interface]
+trait ICounterV3<TContractState> {
+    // get count - retrieve the count from storage
+    // a read-only function
+    fn get_count(self: @TContractState) -> u32;
+    // set count
+    fn set_count(ref self: TContractState, amount: u32);
+    // add owner
+    fn add_new_owner(ref self: TContractState, new_owner: ContractAddress);
+    // increase count by one
+    fn increase_count_by_one(ref self: TContractState);
+    // decrease count by one
+    fn decrease_count_by_one(ref self: TContractState);
+    // get current owner
+    fn get_current_owner(self: @TContractState) -> ContractAddress;
+}
+
+#[starknet::contract]
+mod CounterV3 {
+    use core::num::traits::Zero;
+    use super::ICounterV3;
+    use starknet::{ContractAddress, get_caller_address};
+
+    #[storage]
+    struct Storage {
+        count: u32,
+        owner: ContractAddress
+    }
+
+    #[constructor]
+    fn constructor(ref self: ContractState, _owner: ContractAddress) {
+        self.owner.write(_owner)
+    }
+
+    #[abi(embed_v0)]
+    impl CounterV3Impl of super::ICounterV3<ContractState> {
+        fn get_count(self: @ContractState) -> u32 {
+            self.count.read()
+        }
+        fn set_count(ref self: ContractState, amount: u32) {
+            // can only be executed by the contract deployer (state-changing)
+            self.only_owner();
+            self.count.write(self.get_count() + amount)
+        }
+        fn add_new_owner(ref self: ContractState, new_owner: ContractAddress) {
+            self.only_owner();
+
+            assert(!self.is_zero_address(new_owner), '0 address');
+
+            assert(self.get_current_owner() != new_owner, 'same owner');
+
+            self.owner.write(new_owner);
+        }
+
+        // increase count by one
+        fn increase_count_by_one(ref self: ContractState) {
+            // can only be executed by the contract deployer (state-changing)
+            assert(self.get_count() < 50, 'count too high');
+            self.count.write(self.get_count() + 1)
+        }
+
+        // decrease count by one
+        fn decrease_count_by_one(ref self: ContractState) {
+            // can only be executed by the contract deployer (state-changing)
+            self.count.write(self.get_count() - 1)
+        }
+
+        // util function to get current owner
+        fn get_current_owner(self: @ContractState) -> ContractAddress {
+            self.owner.read()
+        }
+    }
+
+    #[generate_trait]
+    impl Private of PrivateTrait {
+        fn only_owner(self: @ContractState) {
+            // get function caller
+            let caller = get_caller_address();
+
+            // get owner of CounterV2 contract
+            let current_owner: ContractAddress = self.owner.read();
+
+            // assertion logic
+            assert(current_owner == caller, 'caller is not owner');
+        }
+
+        fn is_zero_address(self: @ContractState, account: ContractAddress) -> bool {
+            if account.is_zero() {
+                return true;
+            }
+            return false;
+        }
+    }
+}
+
+// 0xfae52025fdff77f2ab38dd5eaa9a23540fbf7131e896d8b5699e2642944e33
+// 0x1fa34f58aa881cb66e01a2156adca02e948a44351072d20d7d381783447bc2e
\ No newline at end of file
diff --git a/src/lib.cairo b/src/lib.cairo
index ca2e0ce..462909c 100644
--- a/src/lib.cairo
+++ b/src/lib.cairo
@@ -1,5 +1,6 @@
 mod counter_v1;
 mod counter_v2;
+mod counter_v3;
 mod student_registry;
 pub mod student_struct;
 pub mod errors;
diff --git a/src/student_registry.cairo b/src/student_registry.cairo
index 9a405a3..75faa62 100644
--- a/src/student_registry.cairo
+++ b/src/student_registry.cairo
@@ -18,7 +18,7 @@ mod StudentRegistry {
     use starknet::{ContractAddress, get_caller_address};
     use super::{IStudentRegistry, Student};
     use core::num::traits::Zero;
-  
+
     use starknet::storage::{
         StoragePointerReadAccess, StoragePointerWriteAccess, StoragePathEntry, Map
     };