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

typedef double ld;

int main()
{
	long long X, Y, N;
	ld r;
	while ( cin >> X >> Y >> N >> r )
	{
		if ( X == 0 && Y == 0 && N == 0 && r == 0.0 )
			break;
		/*
		ld a = ( 1.0 + (ld)r / 12.0 );
		cout << "a: " << a << "\n";
		ld an = pow( a, (ld)N * 12 );
		cout << "an: " << an << "\n";
		ld s = X * ( an * (a - 1) / (an - 1) );
		cout << "s: " << s << " " << Y * 12 * N << "\n";
		if ( s >= Y * 12 * N )
			cout << "NO\n";
		else
			cout << "YES\n";
			*/
		
		long double B = (long double)X;
		for ( int i = 0; i < N; ++i )
		{
			for ( int j = 0; j < 12; ++j )
			{
				ld add = B * (r / 1200.0);
//				cout << "add: " << add << "\n";
//				cout << "Y: " << Y << "\n";
				if ( add > Y )
				{
					goto end;
				}
				B += add;
				B -= Y;
//				cout << "B: " << B << "\n";
			}
		}
		
		end:
		if ( B > 0.0 )
			cout << "NO\n";
		else
			cout << "YES\n";
	}
	return 0;
}