#include <bits/stdc++.h>
using namespace std;
long long power(long long x, long long p) {
  if (p == 0) return 1ll;
  long long ans = power(x, p / 2);
  ans *= ans;
  if (p & 1) ans *= x;
  return ans;
}
char CC[100050];
int b[55];
int main() {
  int n;
  cin >> n;
  cin >> CC;
  for (int i = 0; i < n; ++i) b[CC[i] - 'a']++;
  int r = 0;
  for (int i = 0; i < 44; ++i)
    if (b[i] == 1) ++r;
  if (r == n && n > 1) return puts("No");
  puts("Yes");
  return 0;
}
