//============================================================================
// Name        : mortage.cpp
// Author      : 
// Version     :
// Copyright   : Your copyright notice
// Description : Hello World in C++, Ansi-style
//============================================================================

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

int main() {
	int X, Y, N;
	double x;
	double r;
	while(1){
		scanf("%i %i %i %lf",&X,&Y,&N,&r);
		if( X == 0 && Y == 0 && N == 0 ) break;
		N = N * 12;

		double u = 1+r/1200;

		x = X * pow(u,N-1)- Y * (pow(u,N-1)-1)/(u-1);

		//printf("%lf\n",x);

		/*
		x = X;
		for( int i = 0; i < N; i++ ) {
			x = x + x*r/1200 - Y;
			if( x <= 0 ) break;
			if( x > X ) break;
		}
		printf("%lf\n",x);
*/

		if( x <= 0 ) {
			printf("YES\n");
		} else {
			printf("NO\n");
		}
	}
	return 0;
}