#include <iostream>



double mocnina(double a,int n)
{
double * temp=new double[20];
double * end(temp + 20);

temp[0]=a;
double * tmp(temp);
for (double * pnter(temp+1);pnter!=end;++pnter,++tmp)
	*pnter=(*tmp)*(*tmp);	

int exp(1024*512);
double res(1);

while(n)
{
	if (n >=exp)
	{
		n -= exp;
		res *= *tmp;
	}
	else
	{
		--tmp;
		exp/=2;
	}
}
	
return res;
}

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

	while( true ) {

		scanf( "%i %i %i %lf", &X,&Y,&N,&r);
		if( X == 0 && Y == 0 && N == 0 && r == 0 ) break;


		if (r==0)
		{
			if( X > Y*N*12 ) 
				printf( "NO\n" );
			else
				printf( "YES\n" );
		}
		else
		{
		r=1+(r / 1200);
		double rn(mocnina(r,N*12));
		double rest(X);
		double y(Y);	

		// all double from now	
			
		if( rest*rn > y*(rn-1)/(r-1) ) 
			printf( "NO\n" );
		else
			printf( "YES\n" );
		}
	}

	return 0;
}