There is a customer that always comes to a store and buys 6 different products, but the problem is that he always takes too much time chosing and trying the products because he needs that the average of the products gives an exact number.

Input

As input you will be given 6 lines, each with the cost of one of the products.

Output

Your problem should output the average cost of the products.

Example

Input:
3
7
5
2
1
6

Output:
4