#include <bits/stdc++.h>
using namespace std;

int main(){
    int L, R, M, K;
    cin >> L >> R >> M >> K;
    int64_t mn = L%M, mx = R%M;
    if(L/M != R/M){
        mn = 0;
        mx = M-1;
    }
    mn *= K;
    mx *= K;
    bool ok = (mn%M == 0 || mn/M != mx/M);
    cout << (ok ? "Yes" : "No") << endl;
    return 0;
}