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

int main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    int n; cin >> n;
    vector<int> a(n);
    for (int &x : a) cin >> x;
    cout << (any_of(a.begin(), a.end(), [](int x){return x > 0;}) ? "Yes" : "No") << "\n";
    return 0;
}