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

int skus(double x, double y, double n, double r)
{
	int mesi, mest;
	double mesu;
	mest = n * 12;
	mesu = 1+r/1200;
	for (mesi=0; mesi<mest; mesi++) {
		x = x * mesu;
		x = x - y;
		if (x<=0) return 1;
		if ((mest-mesi-1)*y<x) return 0;
	}
	return 0;
}

int main(void)
{
	double x,y,n,r,q;
	while (1) {
		q=scanf("%lf %lf %lf %lf\n", &x, &y, &n, &r);
		if (q != 4) break;
		if (x==0.0 && y==0.0 && n==0.0 && r==0.0) break;
		//printf("%f %f %f %f\n", x,y,n,r);
		printf("%s\n", skus(x,y,n,r)?"YES":"NO");
	}
	return 0;
}