#define _USE_MATH_DEFINES	//M_PI(3.14)
#include <iostream>			//std::cout, std::cin
#include <string>			//std::string
#include <vector>			//std::vector
#include <valarray>			//std::valarray	数値のみの一次配列
#include <algorithm>		//std::sort
#include <time.h>			//localtime_s
#include <cstdlib>			//abs
#include <cmath>			//abs, std::pow, sqrt, sin, cos,round,floor
#include <fstream>			//std::ifstream
#include <iomanip>			//std::setprecision
#include <random>			//std::random(C++11)
#include <numeric>			//std::accumulate

int main(void) {

	//test用
	//std::ifstream in("test.txt");
	//std::cin.rdbuf(in.rdbuf());

	//const unsigned int MODULO = 1000000007;	//MODULO 10^9+7用

	unsigned long long H, W, N, K, ans;
	std::cin >> H >> W >> N >> K;

	ans = (H*W) % N;
	if (ans != 0) {
		if (ans == K) {
			std::cout << "YES" << std::endl;
		}
		else {
			std::cout << "NO" << std::endl;
		}
	}
	else {
		if (N == K) {
			std::cout << "YES" << std::endl;
		}
		else {
			std::cout << "NO" << std::endl;
		}
	}
}