#include <bits/stdc++.h>
using namespace std;
char a[1000001];
int b[100], n;
int s, l;
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
    b[a[i] - 'a' + 1]++;
  }
  for (int i = 1; i <= 26; i++) {
    if (b[i] > 1) s++;
    if (b[i] > 0) l++;
  }
  if (l == 1) {
    cout << "Yes";
    return 0;
  }
  if (s >= 1)
    cout << "Yes";
  else {
    cout << "No";
  }
  return 0;
}
