#include <bits/stdc++.h>
using namespace std;
using ll = long long;



void solve(){
    int N; cin >> N;
    bool ok = false;
    for(int i = 0; i < N; ++i){
        int A; cin >> A;
        if(A != 0) ok = true;
    }
    if(ok) cout << "Yes\n";
    else cout << "No\n";
}


int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << setprecision(10) << fixed;


    int T;
    T = 1;
    //cin >> T;
    for(;T--;) solve();
}