#!/usr/bin/env python

import math						# An example of module.

def prime(val):						# prime() function returns:						
	val=abs(val)					# 0 -> number is prime;
	if val == 0 | val == 1:				# 1 -> number isn't prime.
		return 1
	elif val != 2:
		if val%2 == 0:
			return 1
		else:
			lim=int(math.sqrt(val)+1)	# The '.' operator is used
			for div in xrange(3,lim,2):	# to call the functions
				if val%div == 0:	# from the modules.
					return 1
	return 0
							# Here starts the main
prm=0							# program.
for a in xrange(-1000,1000):				# 'xrange' increases of 1
	for b in xrange(-1000,1000):			# if not differently spe-
		n=0					# cified.
		while prime(n*n+a*n+b)==0:
			n=n+1					
		if n > prm:
			res=a*b
			prm=n
print res