#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define ll long long
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define repl(i,a,b) for(ll i=(a);i<(b);i++)
#define all(a) (a).begin(),(a).end()

template <typename T> bool chmin(T &a,T b){if(a>b){a=b;return true;} return false;}
template <typename T> bool chmax(T &a,T b){if(a<b){a=b;return true;} return false;}

int main(){
  int n; cin >> n;
  vector<int> a(n);
  rep(i,0,n){
    cin >> a[i];
    if(a[i] != 0){
      cout << "Yes" << endl;
      return 0;
    }
  }

  cout << "No" << endl;
}