#include <bits/stdc++.h>   using namespace std;   long long ar[200010];   void solve() {     long long a, b, c = 0, i, j, t, k, lie, m, n, o, x, y, z;     long long p = 0, sm = 0, cnt = 0;     scanf( %lld , &n);     string s;     cin >> s;     if (n == 1) {       printf( Yes n );       return;     }     for (i = 0; i < n; i++) ar[s[i] -  a ]++;     for (i = 0; i < 26; i++) {       if (ar[i] > 1) {         printf( Yes n );         return;       }     }     printf( No n );   }   int main() {     solve();     return 0;   }   