#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, cnt = 0, cnt2 = 0;
  scanf("%i", &n);
  if (n == 1) return 0 * printf("Yes\n");
  vector<int> freq(1000);
  string s;
  cin >> s;
  for (int x = 0; x < n; x++) freq[s[x] - 'a']++;
  for (int x = 0; x < 26; x++)
    if (freq[x] == 1)
      cnt++;
    else if (freq[x] > 1)
      cnt2++;
  if (cnt2 || !cnt)
    printf("Yes\n");
  else
    return 0 * printf("No\n");
}
