n1 = raw_input("Please enter a number.")
n1 = int(n1)
n2 = raw_input("Please enter a number.")
n2 = int(n2)
n3 = raw_input("Please enter a number.")
n3 = int(n3)
n4 = raw_input("Please enter a number.")
n4 = int(n4)

sums = n1 + n2 + n3 + n4
print sums

avg = sums / 4