Given three integers $a$ , $b$ , and $c$ . Find their arithmetic mean.

Three integers $a$ , $b$ , and $c$ are given ( $1 \le a, b, c \le 10^9$ ).

Print the arithmetic mean of the three numbers.

Example 1

Input

4 5 6

Output

Example 2

Input

5 11 47

Output

Example 3

Input

2 3 5

Output

3.3333

Arithmetic Averages