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 C# (Mono-csc 3.5.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Numerics;
using static System.Console;
using static System.Math;
using static System.Array;

class Program
{
    public static void Main()
    {
        var n = ReadLine().Split().Select(int.Parse).ToArray();
        WriteLine(n[0] + n[1] < 10 ? (n[0] + n[1]).ToString() : "error");
    }
}