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 4.6.2.0) (judge verdict: Runtime Error)

using System;
using System.Linq;

public class Solution
{
    public static bool CanKillAll(int[] enemies, long turn, int basicDamage, int exDamage)
    {
        long d = basicDamage * turn;
        var remain = enemies.Select(hp => hp - d).Where(hp => hp > 0);
        foreach (var hp in remain)
        {
            var t = (hp + exDamage - 1) / exDamage;
            turn -= t;
            if (turn < 0)
            {
                return false;
            }
        }
        return true;
    }

    public static void Main()
    {
        var vals = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
        var n = vals[0];
        var a = vals[1];
        var b = vals[2];
        var enemies = new int[n];
        for (int i = 0; i < n; i++)
        {
            enemies[i] = int.Parse(Console.ReadLine());
        }


        var basicDamage = b;
        var exDamage = a - b;

        var max = enemies.Max();
        long minRange = max / a;
        long maxRange = max / b;

        while (minRange != maxRange)
        {
            var turn = (minRange + maxRange) / 2;
            bool can = CanKillAll(enemies, turn, basicDamage, exDamage);
            if (can)
            {
                maxRange = turn;
            }
            else
            {
                minRange = turn + 1;
            }
        }

        Console.WriteLine(minRange);
    }
}