#include <bits/stdc++.h>
using namespace std;
#define REP(i,n) for(int i=0; i<(n); i++)
#define D(x) for_each((x).begin(),(x).end(),[](auto& x){cout<<x<<" ";});
using ULL=unsigned long long;
struct cww{cww(){ios::sync_with_stdio(false);cin.tie(0);}}star;
int main()
{
	ULL H, W, N, K;
	cin >> H >> W >> N >> K;
	cout << ( ( H * W ) % N == K % N ? "YES" : "NO" ) << endl;
	return 0;
}