#include <iostream>
#include <string>
#include <vector>
#include <cmath>
#include <algorithm>
#include <cstdlib>
#include <ctime>
#include <cstdio>
#include <functional>
#include <set>
#include <sstream>
#include <map>
#include <queue>
#include <stack>

using namespace std;
 
const unsigned long long mod = 1000000000+7;

int main()
{
	unsigned long long h,w,n,k;
	cin>>h>>w>>n>>k;

	unsigned long long rest=(h*w)%n;

	if(rest==(k%n)) cout<<"YES"<<endl;
	else cout<<"NO"<<endl;

	return 0;
}