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: Accepted)

# 二つの整数 A, B が入力されます。
# A+B の値を出力してください。
# ただし、A+B が 10 以上の場合は、代わりに error と出力してください。

input_line = gets.chomp.split
a = input_line[0].to_i
b = input_line[1].to_i

if a + b >= 10
  puts "error"
else
  puts a + b
end