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
/*
    Problem URL : https://beta.atcoder.jp/contests/abc063/tasks/abc063_a

    Score  :
    Result :
    Time   : ms
    Memory : KB
 */


// define('DEBUG', true);
define('DEBUG', false);

ini_set('error_reporting', E_ALL & ~E_NOTICE);

fscanf(STDIN, "%d %d", $A, $B);

if ($A + $B >= 10) {
    echo "error\n";
} else {
    echo ($A + $B) . PHP_EOL;
}