#include <bits/stdc++.h>
using namespace std;
using ll = long long;
constexpr long long MOD = 1000000007;
int main(){
    ll l, r, m, k;
    ll mini = 1e12;
    ll maxi = 0;
    cin >> l >> r >> m >> k;
    for (ll i = k * l; i <= k * r; i++) {
        if(i%m==0){
            cout << "Yes" << endl;
            return 0;
        }
    }
    cout << "No" << endl;
}