#include <bits/stdc++.h>
using namespace std;
const double PI = acos(-1.0);
const double eps = 1e-6;
const long long mod = 1e9 + 7;
const int inf = 0x3f3f3f3f;
const int maxn = 2e5 + 10;
const int maxm = 100 + 10;
char s[maxn];
int a[maxn];
int main() {
  int n;
  cin >> n;
  cin >> s;
  map<char, int> mp;
  for (int i = 0; i < n; i++) mp[s[i]]++;
  int flag = 0;
  for (int i = 0; i < n; i++) {
    if (mp[s[i]] >= 2) {
      flag = 1;
      break;
    }
  }
  if (n == 1) flag = 1;
  if (flag)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
