#include <cstdio>

int main(){
    long long H, W, N, K;
    scanf("%lld %lld %lld %lld", &H, &W, &N, &K);

    if(N == 1){
        puts("YES");
    }else if(H * W % N == 0){
        puts(K == N ? "YES" : "NO");
    }else{
        puts(H*W%N == K ? "YES" : "NO");
    }
}