diff --git a/src/main/java/gpacalc/Application.java b/src/main/java/gpacalc/Application.java
index 57e79e1..b8bae78 100644
--- a/src/main/java/gpacalc/Application.java
+++ b/src/main/java/gpacalc/Application.java
@@ -1,7 +1,141 @@
 package gpacalc;
 
+import java.util.Scanner;
+
 public class Application {
+
     public static void main(String[] args) {
-        //TODO: 구현
+        Scanner in = new Scanner(System.in);
+
+        System.out.println("전공 과목명과 이수학점, 평점을 입력해주세요(예시: 프로그래밍언어론-3-A+,소프트웨어공학-3-B+):");
+        String majorLine = in.nextLine();     // 전공 입력
+
+        System.out.println("교양 과목명과 이수학점, 평점을 입력해주세요(예시: 선형대수학-3-C0,인간관계와자기성장-3-P):");
+        String generalLine = in.nextLine();   // 교양 입력
+
+        // 변수들 생성하기
+        int getCredits = 0;
+
+        double totalWeightedSum = 0.0;
+        int totalGpaCredits = 0;
+
+        double majorWeightedSum = 0.0;
+        int majorGpaCredits = 0;
+
+        System.out.println("<과목 목록>");
+
+        // 전공수업 확인하기
+        String[] majors = majorLine.split(",");
+        for (String raw : majors) {
+            String[] info = parseAndValidate(raw); // [0]=name, [1]=credit, [2]=grade
+            String name = info[0];
+            int credit = parseCredit(info[1]);
+            String grade = info[2];
+
+            System.out.println("[전공] " + name + "," + credit + "," + grade);
+
+            // 취득학점: F, NP 제외
+            if (!grade.equals("F") && !grade.equals("NP")) {
+                getCredits += credit;
+            }
+
+            // 평점평균: P, NP 제외
+            if (!grade.equals("P") && !grade.equals("NP")) {
+                double point = toPoint(grade);
+
+                totalWeightedSum += point * credit;
+                totalGpaCredits += credit;
+
+                majorWeightedSum += point * credit;
+                majorGpaCredits += credit;
+            }
+        }
+
+        // 교양과목 확인
+        String[] generals = generalLine.split(",");
+        for (String raw : generals) {
+            String[] info = parseAndValidate(raw);
+            String name = info[0];
+            int credit = parseCredit(info[1]);
+            String grade = info[2];
+
+            System.out.println("[교양] " + name + "," + credit + "," + grade);
+
+            // 취득학점: F, NP 제외
+            if (!grade.equals("F") && !grade.equals("NP")) {
+                getCredits += credit;
+            }
+
+            // 평점평균: P, NP 제외
+            if (!grade.equals("P") && !grade.equals("NP")) {
+                double point = toPoint(grade);
+
+                totalWeightedSum += point * credit;
+                totalGpaCredits += credit;
+            }
+        }
+
+        System.out.println("<취득학점>");
+        System.out.println(getCredits + "학점");
+
+        System.out.println("<평점평균>");
+        double totalGpa = totalWeightedSum / totalGpaCredits;
+        System.out.printf("%.2f/4.5\n", totalGpa);
+
+        System.out.println("<전공 평점평균>");
+        double majorGpa = majorWeightedSum / majorGpaCredits;
+        System.out.println(majorGpa+"/ 4.5");
+    }
+
+    // 과목명-학점-성적 -이걸로 split 하고 길이 확인하기
+    private static String[] parseAndValidate(String raw) {
+        String t = raw.trim();
+        String[] parts = t.split("-");
+        if (parts.length != 3)
+            throw new IllegalArgumentException();
+
+        String name = parts[0].trim();
+        String credit = parts[1].trim();
+        String grade = parts[2].trim();
+
+
+        validateGrade(grade); //검증해줘야 나중에 오류 X
+
+        return new String[]{name, credit, grade};
+    }
+
+    private static void validateGrade(String grade) {
+        String[] allowed = {"A+","A0","B+","B0","C+","C0","D+","D0","F","P","NP"};
+        for (String g : allowed) {
+            if (g.equals(grade))
+                return;
+        }
+        throw new IllegalArgumentException();
+    }
+
+    // 학점 문자열 -> int 변환 + 1~4 확인하기
+    private static int parseCredit(String creditStr) {
+        int credit;
+        try {
+            credit = Integer.parseInt(creditStr);
+        } catch (NumberFormatException e) {
+            throw new IllegalArgumentException();
+        }
+        if (credit < 1 || credit > 4) throw new IllegalArgumentException();
+        return credit;
+    }
+
+    private static double toPoint(String grade) {
+        if (grade.equals("A+")) return 4.5;
+        if (grade.equals("A0")) return 4.0;
+        if (grade.equals("B+")) return 3.5;
+        if (grade.equals("B0")) return 3.0;
+        if (grade.equals("C+")) return 2.5;
+        if (grade.equals("C0")) return 2.0;
+        if (grade.equals("D+")) return 1.5;
+        if (grade.equals("D0")) return 1.0;
+        if (grade.equals("F"))  return 0.0;
+        throw new IllegalArgumentException();
     }
 }
+