#include <stdio.h>


int main()
{
	double borrowed, interest, prirust;
	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;
	int navrat = 0;
	interest = (interest/1200)+1;
	prirust = borrowed*interest-borrowed;
	if(prirust >= mpay)
	{
		printf("NO\n");
		continue;
	}
	years=years*12;
	for(int i =0;i<years;i++)
	{
		borrowed = borrowed*interest;
		borrowed -= mpay;
		if(borrowed <=0)
		{
			navrat=1;
		}
	}
	if(navrat)
		printf("YES\n");
	else
		printf("NO\n");
	  
}
	

return 0;
}