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 Scala (2.11.7) (judge verdict: Runtime Error)

import scala.io.Source

object Main {

  def main(args: Array[String]) {
    val lines = Source.stdin.getLines.toSeq
    val n = lines.head.split(" ")(0).toLong
    val a = lines.head.split(" ")(1).toLong
    val b = lines.head.split(" ")(2).toLong
    val hs = lines.tail.map(_.toLong)
    var min_count = a * n

    def burn(xs: Seq[Long], count: Long) {
      if (min_count < count) {

      } else if (xs.isEmpty) {
        min_count = count
      } else {
        val ys = xs.zipWithIndex
        for ((x, i) <- ys) {
          burn(ys.map {
            case (x2, i2) if i == i2 => x2 - a
            case (x2, i2) => x2 - b
          }.filter(_ > 0), count + 1)
        }
      }
    }

    burn(hs, 0)
    println(min_count)
  }
}