#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (n);i++)
#define sz(x) int(x.size())
typedef long long ll;
typedef pair<int,int> P;
constexpr int INF = 2e9;

vector<long long> divisor(long long n){
    vector<long long> res;
    for(long long i = 1; i*i <= n; i++){
        if(n%i==0){
            res.push_back(i);
            if(n/i != i)res.push_back(n/i);
        }
    }
    return res;
}

int main() {
  int l, r, m, k;
  cin >> l >> r >> m >> k;
  if (k == 0) {
    cout << "Yes" << endl;
    return 0;
  }
  bool ok = false;

  auto check = [&](int x) {
    if (x < l || r < x) return false;
    int cnt = m / x;
    return cnt <= k;
  };

  for (ll i = 1; i * i <= m; i++) {
    if (m % i == 0) {
      if (check(i)) ok = true;
      if (m / i != i) {
        if (check(m/i)) ok = true;
      }
    }
  }

  if (ok) cout << "Yes" << endl;
  else cout << "No" << endl;

  return 0;
}