#include <bits/stdc++.h>
using namespace std;
int n;
int ch[30];
char a[100010];
int main() {
  bool flag = 0;
  cin >> n;
  if (n == 1) {
    cout << "Yes";
    return 0;
  }
  cin >> a + 1;
  for (int i = 1; i <= n; i++) {
    int s = a[i] - 'a';
    ch[s]++;
  }
  for (int i = 0; i <= 26; i++) {
    if (ch[i] != 0 && ch[i] != 1) {
      flag = 1;
    }
  }
  if (flag)
    cout << "Yes";
  else
    cout << "No";
  return 0;
}
