#include <bits/stdc++.h>
 
using namespace std;
 
int main()
{
    // cout << fixed << setprecision(9);
 
    double a, b, c, d;
    cin >> a >> b >> c >> d;
    cout << ((b * log(a) > d * log(c)) ? "YES" : "NO");
 
    return 0;
}
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