#include <bits/stdc++.h>

using namespace std;

void fast_io() {
	ios::sync_with_stdio(false);
	std::cin.tie(nullptr);
}

int main() {
	fast_io();
	int n;
	cin >> n;
	vector<int> a(n);
	int ma = 0;
	for (int i = 0; i < n; i++) {
		cin >> a[i];
		ma = max(ma, a[i]);
	}
	cout << (ma ? "Yes" : "No") << endl;
}