first rep let

#include <bits/stdc++.h>
using namespace std;

bool fol[26], ok = true;

int main()
{
    char c[100];
    cin.getline(c,100);
    for (int i = 0; c[i] && ok; i++)
        if (!fol[c[i] - 'a'])
            fol[c[i] - 'a'] = true;
        else
        {
            cout<<c[i]<<endl;
            ok = false;
        }
    if (ok)
        cout<<"nici o litera nu se rep";
    return 0;
}