#!/usr/bin/python3

N = int(input())

if N == 0:
	print(0)
	exit(0)

prunik = [int(x) for x in input().split()]
funkce = [max,min] * 3

for _ in range(1,N):
	kvadr = [int(x) for x in input().split()]
	for i in range(6):
		prunik[i] = funkce[i](prunik[i],kvadr[i])

intervaly = zip(prunik[::2],prunik[1::2])
objem = 1
for a, b in intervaly:
	if a > b:
		objem = 0
	else:
		objem *= b-a

print(objem)