#include <bits/stdc++.h>
using namespace std;
string s;
map<char, int> u;
int main() {
  cin >> s >> s;
  for (auto x : s) ++u[x];
  if (u.size() == 1) return puts("Yes"), 0;
  for (auto& x : u)
    if (x.second >= 2) return puts("Yes"), 0;
  puts("No");
}
