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 PHP7 (7.0.15) (judge verdict: Accepted)

<?php
list($a, $b) = ints();
echo $a + $b >= 10 ? 'error' : $a + $b;
function ints()
{
    return array_map('intval', explode(' ', trim(fgets(STDIN))));
}