#include <iostream>

using namespace std;

int main()
{
	long X,Y;
	long double D;
	int N;
	float r;

	cin >> X >> Y >> N >> r;
	while (X != 0) {
		D = X;
		for (int y = 0; y < N; ++y) {
			for (int m = 0; m < 12; ++m) {
				D += D * (r/1200.0);
				D -= Y;
				if (D <= 0) break;
			}
			if (D <= 0) break;
		}
		if (D <= 0) cout << "YES\n";
		else cout << "NO\n";

		cin >> X >> Y >> N >> r;
	}
	return 0;
}