#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 R = r%m;
    ll L = l%m;
    if (k == 1) cout << "No" <<endl;
    else  if (L < m/2 && m/2 <= R) cout << "Yes" <<endl;
    else {
      if (L >= m/2) {
        ll LL = L;
        L = m-R;
        R = m - LL;
      }
      ll b = m/L;
      ll s;
      if (m%R==0) s = m/R;
      else s = m/R + 1;

      if (s<=k&&k<=b) cout << "Yes" <<endl;
      else cout << "No" <<endl;
    }
  }
}