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

int main(int argc, char** argv){
	double x,y,n,r,debt, debt_old;
	int i;
	unsigned char flag;
	while(1){
		scanf("%lf %lf %lf %lf", &x, &y, &n, &r);
		if(x==0 && y==0 && n==0 && r==0){
			break;
		}
		n *= 12;
		debt = x*pow((1+(r/1200)),n) - n*y;

/*		debt = x;
		flag = 0;
		for(i = 1; i <= n; i++){
			debt_old = debt;
			debt = debt*(1+r/1200) - y;
			if(debt <= 0){
				printf("YES\n");
				flag = 1;
				break;
			}
			if(debt_old <= debt){
				printf("NO\n");
				flag = 1;
				break;
			}
//			printf("%d : %f\n", i, debt);
		}
//		printf("%f\n", debt);
		
		if(flag == 0)
			printf("NO\n");
*/
	if(debt <= 0) printf("YES\n"); else printf("NO\n");

	}
	return 0;
}