#define  _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <algorithm>
#include <utility>
#include <functional>
#include <cstring>
#include <queue>
#include <stack>
#include <math.h>
#include <iterator>
#include <vector>
#include <string>
#include <set>
#include <math.h>
#include <iostream> 
#include<map>
#include <iomanip>
#include <time.h>
#include <stdlib.h>
#include <list>
#include <typeinfo>
#include <list>
#include <set>
using namespace std;
#define eps 0.000000001
#define LONG_INF 10000000000000000
#define MAX_MOD 1000000007
#define REP(i,n) for(long long i = 0;i < n;++i)
int main() {
	double x, y;
	cin >> x >> y;
	x /= 3.6;
	y /= 3.6;
	vector<double> hoge;
	int h = 0;
	cin >> h;
	REP(i, h) {
		double a;
		cin >> a;
		hoge.push_back(a);
	}
	for (int i = 0;i < h - 1;++i) {
		double time = hoge[i] / x;
		double sisyo_time = hoge[i + 1] / y;
		if (sisyo_time-time < -1 * eps) {
			cout << "NO" << endl;
			return 0;
		}
	}
	cout << "YES" << endl;
	return 0;
}