#include <iostream>
#include <cmath>
using namespace std;

double fce(double dluh,int splatka,int mesicu,double urok){
	if (mesicu<=0) return dluh;
	if (dluh<=0) return 0;
	return fce(dluh*urok-splatka, splatka, mesicu-1,urok);
}

int main(void){
	int splatka, mesicu;
	double urok, dluh,celkem;	

	while(1){
		cin >> dluh >> splatka >> mesicu >> urok;

		if(dluh + splatka + mesicu + urok == 0)
			break;

		mesicu *= 12;
		urok = urok/1200 + 1;

		//if (fce(dluh, splatka, mesicu, urok) <=0) cout << "YES" << endl;
		//else cout << "NO" << endl;

		celkem = (dluh*pow(urok,mesicu))-((splatka*pow(urok,mesicu-1))*(pow(1/urok,mesicu-1)-1)/(1/urok-1))-splatka;

		if(celkem<=0)cout << "YES" << endl;
		else cout << "NO" << endl;
	
		
	}

	return 0;
}