using namespace std;
#include <bits/stdc++.h>
#define BEGIN ios_base::sync_with_stdio(0);cin.tie(0);
#define END return EXIT_SUCCESS;
#define FOR(I,A,B) for(int (I)=(A);(I)<(B);++(I))
#define ALL(C) (C).begin(),(C).end()
void solve()
{
	int H,W,N,K;cin>>H>>W>>N>>K;
	int M=H*W;
	int T=M%N;
	int V=T?T:N;
	cout<<(V==K?"YES":"NO")<<endl;
}
int main(int argc,char**argv)
{
	BEGIN
	solve();
	END
}