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 Ruby (2.3.3) (judge verdict: Runtime Error)

n = gets.chomp.to_i
sum = 0
score = []

n.times do |i|
    score[i] = gets.chomp.to_i
    sum += score[i]
end

(score.length - 1).times do
    (score.length - 1).times do |k|
        if score[k] > score[k+1] then
            buf = score[k]
            score[k] = score[k+1]
            score[k+1] = buf
        end
    end
end

l = 0
while true do
    flag = false 
    if sum % 10 == 0 then
            flag = true
            sum -= score[l]
    end
    if flag != true ; break
    end
    l += 1
end

puts sum