#include<cstdio>
#include <iostream>
#include<algorithm>
#include<string>
#include<queue>
#include<vector>
#include<functional>
#include<cmath>
#include<map>
#include<stack>
#include<set>
#include<numeric>

using namespace std;
typedef long long ll;
typedef pair<int, int> Pr;

double X, Y;
int N;
double A[81];

int main()
{
	cin >> X >> Y >> N;
	X = (X * 1000) / (60 * 60);
	Y = (Y * 1000) / (60 * 60);

	for (int i = 0; i < N; i++)
		cin >> A[i];

	for (int i = 0; i < N-1; i++) {
		double t = A[i] / X;
		int d = t*Y;
		if (t*Y - d > 0.00000001) {
			if ((t * Y) > A[i + 1]) {
				cout << "NO" << endl;
				return 0;
			}
		}
		else {
			if (d > A[i + 1]) {
				cout << "NO" << endl;
				return 0;
			}
		}
	}
	cout << "YES" << endl;
	return	0;
}