#include<iostream>
#include<string>
#include<string.h>
#include<algorithm>
#include<stdio.h>
#include<cmath>
#include<vector>
#include<utility>
#include<stack>
#include<queue>
#include<list>
#include<bitset>
#include<functional>

#define FOR(i, a, b) for(int i=(a);i<=(b);i++)
#define RFOR(i, a, b) for(int i=(a);i>=(b);i--)
#define MOD 1000000007
#define INF 1000000000
#define PI 3.14159265358979

using namespace std;
typedef pair<int, int> P;

int main(void) {
	double x, y;
	int n;
	double a[81];
	double k[81];
	double s[81];
	bool flag = true;

	cin >> x >> y;
	cin >> n;

	x = 5 * x / 18;
	y = 5 * y / 18;

	FOR(i, 1, n) {
		cin >> a[i];
		k[i] = a[i] / x;
		s[i] = a[i] / y;
	}
	FOR(i, 1, n-1) {
		if (k[i] > s[i + 1]) {
			flag = false;
			break;
		}
	}
	if (flag) {
		cout << "YES" << endl;
	}
	else {
		cout << "NO" << endl;
	}
	return 0;
}