#include <algorithm>
#include <cstring>
#include <deque>
#include <iostream>
#include <limits>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
#define rep(i, a, n) for(int i = a; i < n; i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;

int main()
{
    int l, r, m, k;
    cin >> l >> r >> m >> k;
    if(k == 0){
        cout << "Yes" << endl;
        return 0;
    }
    rep(i, l, r+1){
        if(i == m/k){
            cout << "Yes" << endl;
            return 0;
        }
    }
    cout << "No" << endl;
    return 0;
}