/*                                              */
/*      primroot--find least primitive root of p*/
/*                                              */
long primroot(p)
long p;
{
	long i, n, pminus1, prod, r;
	pminus1 = p - 1L;
	for (r = 2L; r <= pminus1; r++)
	{
		prod = 0L;
		n = 1L;
		for( i=1L; (i<=pminus1) && (prod!=1L); i++)
		{
			prod = (n*r) % p;
			n = prod;
		}
		if (i == p)
			if (prod == 1L)
				return(r);
			else
				return(0L);
	}
}