#include <stdio.h>
#define DEBUG 1
#define III if(DEBUG)
#define LEN 1000010

int main() {
  long double X,Y,r;
  int N;
  
  scanf("%Lf %Lf %d %Lf\n", &X, &Y, &N, &r);
  while( X>0.5 ) {
    if (X*r/1200-Y >=0.) //ci klesa alebo stupa
	  printf("NO\n");
	else {
      //writeOut 
	  for (int i=0; i<N*12; i++) {
	    X +=X*r/1200-Y;
		if (X<=0.)
		  break;
	  }
	  if (X<=0.)
	    printf("YES\n");
	  else
	    printf("NO\n");
	}
	//read next line
	scanf("%Lf %Lf %d %Lf\n", &X, &Y, &N, &r);
  }
  return 0;
}