#include<iostream>
#include<vector>
#include<math.h>

using namespace std;

int main() {

	int x, y, n;
	cin >> x >> y;
	cin >> n;
	vector<int> kousaten;
	for (int i = 0;i < n;i++) {
		int buf=0;
		cin >> buf;
		kousaten.push_back(buf);
	}
	double xs = x * pow(10, 3) / pow(60, 2);
	double ys = y * pow(10, 3) / pow(60, 2);

	int j = 0;
	while (j <= n - 2) {
		double koba_now_s = kousaten[j] / xs;
		double master_p = koba_now_s * ys;
		if (master_p>kousaten[j + 1]) {
			cout << "NO" << endl;
			return 0;
		}
		j++;
	}
	cout << "YES" << endl;

	return 0;
}