#include <cstdio>
#include <iostream>
#include <vector>
#include <cmath>

using namespace std;

typedef long long lli;

double mocni(double z, lli e)
{
	if (!e)
		return 1;
	double res = mocni(z, e >> 1);
	if (e & 1L)
		return res * res * z;
	return res * res;
}

double ostatok(lli X, lli Y, double zakl, double r, lli mesiacov)
{
	double koef = mocni(zakl, mesiacov);
	return X * koef - Y * 1200 * (koef - 1) / r;
}

bool jeZaporne(double x)
{
	return x < .0000000001;
}

int main()
{
	while (47)
	{
		lli X, Y, N;
		double r;
		scanf("%lld%lld%lld%lf", &X, &Y, &N, &r);
		if (!(X+Y+N || (r > 0)))
			return 0;
		if (jeZaporne(r))
		{
			if (N * 12 * Y >= X)
				printf("YES\n");
			else
				printf("NO\n");
			continue;
		}
		lli maxi = 1, mini = 0;
		double zakl = (1200 + r) / 1200;
		if (ostatok(X, Y, zakl, r, maxi) > X)
		{
			printf("NO\n");
			continue;
		}
		//cerr << "    " << X << " " << Y << " " << zakl << " " << r << " " << maxi << endl;
		while (!jeZaporne(ostatok(X, Y, zakl, r, maxi)))
		{
			mini = maxi;
			maxi <<= 1;
		}
		//cerr << "  " << maxi << ", " << mini << endl;
		while ((maxi - mini) > 1)
		{
			lli stred = (maxi + mini) >> 1;
			if (jeZaporne(ostatok(X, Y, zakl, r, stred)))
				maxi = stred;
			else
				mini = stred;
		}
		//cerr << "\t" << mini << ", " << maxi << endl;
		if (mini < 12 * N)
			printf("YES\n");
		else
			printf("NO\n");
	}
}