competitive-programming/DifferentIsGood.cpp at master · tangziyi001/competitive-programming · GitHub

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/*
 *	CodeForces 672B
 *	Created by Ziyi Tang
 *
 */

//#include <bits/stdc++.h>
#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <cstdlib>
#include <sstream>
#include <cmath>
#include <algorithm>
#include <list>
#include <vector>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <bitset>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pi;
typedef vector<pi> vpi;
typedef vector<vpi> vvpi;
const int INF = (int)1E9;
const long INFL = (long)1E18;
const int dir[4][2] = {{-1,0},{0,1},{1,0},{0,-1}};
#define REP(i,s,t) for(int i=(s);i<(t);i++)
#define FILL(x,v) memset(x,v,sizeof(x))
#define MAXN 1000
#define MOD 1000000007

int mark[26];
int main(){
	int n;
	string line;
	cin >> n >> line;
	if(n > 26){
		cout << -1 << endl;
		return 0;
	}
	int re = 0;
	REP(i,0,n){
		mark[line[i]-'a']++;
	}
	REP(i,0,26){
		if(mark[i]>1){
			re+=(mark[i]-1);
		}
	}
	cout << re << endl;
	return 0;
}