#include <iostream>
using namespace std;
typedef long long LL;
int main(int argc, char* argv[])
{
	LL H,W,N,K;
	cin>>H>>W>>N>>K;
	if ((H*W-K)%N==0){
		cout<<"YES"<<endl;
	}else{
		cout<<"NO"<<endl;
	}
	return 0;
}