Problem:
Score : 100 points

Problem Statement

You are given two integers A and B as the input. Output the value of A + B.

However, if A + B is 10 or greater, output error instead.

Constraints

A and B are integers.

1 ≤ A, B ≤ 9

Input

Input is given from Standard Input in the following format:

A B

Output

If A + B is 10 or greater, print the string error (case-sensitive); otherwise, print the value of A + B.

Sample Input 1

6 3

Sample Output 1

9

Sample Input 2

6 4

Sample Output 2

error

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

import Control.Applicative
import Data.List
import Data.Char

getInt :: IO Integer
getInt = (\a -> read a :: Integer) <$> getLine

getIntArray :: IO [Integer]
getIntArray = ((map (\a -> read a :: Integer)) . words) <$> getLine

getStrArray :: Integer -> IO [String]
getStrArray 0 = return [] :: IO [String]
getStrArray n = (:) <$> getLine <*> (getStrArray (n - 1))

main = do
    putStrLn =<< ((\[a, b] -> if a + b >= 10 then "error" else show $ a + b) <$> getIntArray)