nos1 = raw_input("enter nb1")
nos2 = raw_input("enter nb2")
nos3 = raw_input("enter nb3")
nos4 = raw_input("enter nb4")
nos5 = raw_input("enter nb5")

x =(int(nos1) + int(nos2) + int(nos3) + int(nos4) + int(nos5))/5
print x







 
