#include <iostream>

int main(void) {
	long long int amount, payment;
	int time;
	double rate;
	
	while(true) {
		scanf("%lld %lld %d %lf", &amount, &payment, &time, &rate);
		if(!amount && !payment && !time && rate < 1E-4) break;
		
		time *= 12;
		double amountToPay = amount;
		rate = 1 + rate / 1200;
		
		while(time-- > 0 && amountToPay > 0) {
			amountToPay *= rate;
			amountToPay -= payment;
			if(amountToPay < 1E-8) {
				printf("YES\n");
				break;
			}
			else if(time == 0) printf("NO\n");
		}
	}
	
	return 0;
}