#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
ll mod = 1000000007;

ll r(ll x, ll y) {
  if (y == 0) return 1;
  else if (y % 2 == 0) return r(x, y/2) * r(x, y/2) % mod;
  else return x * r(x, (y-1)/2) % mod * r(x, (y-1)/2) % mod;
}

int main() {
  ll l, r, m, k;
  cin >> l >> r >> m >> k;
  vector<bool> ama(m);
  if (k == 0) cout << "Yes" <<endl;
  else if (l%m==0 || r%m==0) cout << "Yes" <<endl;
  else if (l/m != r/m) {
    if (k == 1) cout << "No" <<endl;
    else cout << "Yes" <<endl;
  }
  else {
    ll s = m/k;
    if ((l <= s && s <= r) || (m-r<=s && s<=m-l)) cout <<"Yes"<<endl;
    else cout << "No" <<endl;
  }
}