#include <bits/stdc++.h>
using namespace std;
char s[110000];
int n, k, i, r, a[256];
int main() {
  cin >> n >> s;
  for (i = 0; i < n; i++) (a[s[i]] > 0 ? r = 1 : 0), a[s[i]]++;
  cout << (r == 1 || n == 1 ? "Yes" : "No");
}
