#include <iostream>
#include <cstdio>
#include <vector>
using namespace std;

int main(){
    long long a, b, c, d;
    cin >> a >> b >> c >> d;

    long long minv = a;
    minv = min(minv, b);
    minv = min(minv, c);
    minv = min(minv, d);

    cout << minv << endl;
    return 0;
}
#include<bits/stdc++.h>
using namespace std;
int main(){
  int v, t, s, d;
  cin >> v >> t >> s >> d;
  if(d<v*t || d>v*s)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}