#include <stdio.h>
#include <stdlib.h>
#include <math.h>

double X, Y, r, p, q ;
int    N, n ;

double debt(double q, int exponent)
{
  double tmp ;

  if (exponent == 1)
  {
    return q ;
  }
  else if (exponent % 2)
  {
    tmp = debt(q, (exponent - 1) / 2) ;
    return q * tmp * tmp ;
  }
  else
  {
    tmp = debt(q, exponent / 2) ;
    return tmp * tmp ;
  }
}  
    

int main()
{
  while (1)
  {
    scanf("%lf %lf %d %lf", &X, &Y, &N, &r) ;

    if (N == 0)
      break ;

    N *= 12 ;

    r /= 1200.0 ;

    q = debt(1 + r, N) ;

    if (X * q - Y * (q - 1) / r < 10e-8)
    {
      printf("YES\n") ;
    }
    else
    {
      printf("NO\n") ;
    }
  }    
  return 0 ;
}