#include <iostream>
#include <cmath>

int main(int argc, char** argv)
{
	//printf("%f", pow(2,3));
	while(1)
	{
		int X, Y, N;
		double r;
		scanf("%d %d %d %lf", &X, &Y, &N, &r);
		if(!X && !Y && !N && !r)
			break;
		
		double s = r/1200 + 1.0;
		double max = pow(s, N*12)*X;
		
		if(max - pow(s, N*12) <= 0)
		{
			printf("YES\n");
			continue;
		}
		
		double cur = 0;
		for(int i=0; i<N*12; i++)
		{
			cur = Y + cur*s;
			if(max-cur<0)
				break;
		}
		
		if(max-cur<=0)
			printf("YES\n");
		else
			printf("NO\n");
		
	}
	
	return 0;
}