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

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int N; cin >> N;
    vector<int> A(N);
    bool yes = false;
    for(auto &a : A){
        cin >> a;
        if(a == 0 || a == 1) yes = true;
    }
    if(yes) cout << "Yes" << endl;
    else cout << "No" << endl;
}