#include <bits/stdc++.h>
using namespace std;
int const N = 1e6 + 100;
long long int const LINF = numeric_limits<long long int>::max();
int const INF = numeric_limits<int>::max();
int const BN = 31;
long long int gcd(long long int a, long long int b) {
  return b ? gcd(b, a % b) : a;
}
long long int pow_mod(long long int a, long long int e, long long int m) {
  long long int res = 1;
  while (e) {
    if (e & 1) res = res * a % m;
    a = a * a % m;
    e >>= 1;
  }
  return res;
}
long long int inv_mod(long long int b, long long int m) {
  b %= m;
  long long int x = 0, y = 1, r, q, a = m;
  while (b) {
    q = a / b;
    r = a % b;
    a = b;
    b = r;
    r = x;
    x = y;
    y = r - q * y;
  }
  x += m;
  return x % m;
}
int main() {
  int n;
  cin >> n;
  vector<int> cnt(26, 0);
  string str;
  cin >> str;
  if (n == 1)
    cout << "Yes" << endl;
  else {
    for (int i = 0; i < n; i++) {
      cnt[str[i] - 'a']++;
    }
    int ans = 0;
    for (int i = 0; i < 26; i++) {
      if (cnt[i] > 1) {
        ans = 1;
        break;
      }
    }
    if (ans == 0) {
      cout << "No" << endl;
    } else
      cout << "Yes" << endl;
  }
}
