#include <stdio.h>

int main()
{	
	double X, Y, N, i;
	double r, debt;
	
	scanf("%lf %lf %lf %lf", &X, &Y, &N, &r);
	
	while (X!=0)
	{
		debt=X;
		for (i=1; i<N*12; i++)
		{
			debt=debt-Y;
			debt=debt*((r/100)/12+1);
			if (debt<=0)
				i=N*12;
		}
		
		if (debt>0)
			printf("NO\n");
		else
			printf("YES\n");
		scanf("%lf %lf %lf %lf", &X, &Y, &N, &r);
	}
	return 0;
}