Problem:
Score : 100 points

Problem Statement

You are given two positive integers a and b.
Let x be the average of a and b.
Print x rounded up to the nearest integer.

Constraints

a and b are integers.

1 \leq a, b \leq 100

Input

Input is given from Standard Input in the following format:

a b

Output

Print x rounded up to the nearest integer.

Sample Input 1

1 3

Sample Output 1

2

The average of 1 and 3 is 2.0, and it will be rounded up to the nearest integer, 2.

Sample Input 2

7 4

Sample Output 2

6

The average of 7 and 4 is 5.5, and it will be rounded up to the nearest integer, 6.

Sample Input 3

5 5

Sample Output 3

5

Solution in Haskell (GHC 7.10.3) (judge verdict: Accepted)

main = do
  [a, b] <- (map read . words) <$> getLine
  putStrLn . show $ solved a b

solved:: Int -> Int -> Int
solved a b
  | mab = div ab 2 + 1
  | otherwise = div ab 2
  where
    ab = a + b
    mab = mod ab 2 /= 0