#include <iostream>
#include <string>
#include <cctype>
#include <cstring>
using namespace std;

bool canPay(double x, double y, double n, double r)
{
  double urok = 1 + (r / 1200.0);
  double xx = x;
  if(x > (12.0*n*y)) return false;
  //
  for(int yr = 0; yr < n; yr++)
  {
    for(int m = 0; m < 12; m++)
    {
      x *= urok;
      if(x <= y) return true; // splaceno
      x -= y;
      //
      if (x>=xx)
        return false;
    }
  }
  return false;
}

int main()
{
  double x, y, n, r;
  while(1)
  {
    cin >> x >> y >> n >> r;
    if(x == 0.0 && y == 0.0 && n == 0.0 && r == 0.0)
      break;
    //
    if(canPay(x, y, n, r))
      cout << "YES\n";
    else
      cout << "NO\n";
  }
  return 0;
}