/*                                              */
/*      gcd(a,b)                                */
/*                                              */
long gcd(a,b)
long a, b;
{
	long big, small, rem;
	big = a;
	small = b;
	if (big < 0L)
		big = -big;
	if (small < 0L)
		small = -small;
	if (big == 0L)
		return(small);
	else if (small == 0L)
		return(big);
	else
	{
		rem = big % small;
		while (rem != 0L)
		{
			big = small;
			small = rem;
			rem = big % small;
		}
		return(small);
	}
}