#include <bits/stdc++.h>
using namespace std;
int N;
char S[100004];
int C[26];
int main(int argc, char **argv) {
  ios::sync_with_stdio(false);
  scanf("%d %s", &N, S);
  if (N == 1) {
    printf("Yes\n");
    return 0;
  }
  for (int i = 0; i < N; i++) {
    int c = S[i] - 'a';
    C[c]++;
  }
  int ok = 0;
  for (int i = 0; i < 26; i++)
    if (C[i] >= 2) ok = 1;
  if (ok)
    printf("Yes\n");
  else
    printf("No\n");
  return 0;
}
