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


int main()
{
	double borrowed, interest;
	long mpay;
	int years;
	

  while( true ) {
	scanf("%lf %ld %d %lf",&borrowed, &mpay, &years, &interest);
	if(borrowed == 0 && mpay==0&&years==0&&interest==0)
		break;
	interest = (interest/1200)+1;
	double pw = pow(interest, years*12);
	if(interest == 1)
	{
		borrowed = borrowed - years*12*mpay;
	}
	else
	borrowed = borrowed*pw-mpay*((pw-1)/(interest-1));
//printf("%lf\n", borrowed);
	if(borrowed <= 0)
		printf("YES\n");
	else
		printf("NO\n");
	  
}
	

return 0;
}