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 Perl (v5.18.2) (judge verdict: Wrong Answer)

($N,$A,$B,@@)=glob`dd`;
$a=($%=1<<30)-1;
map{
  $==$i=$a-$%;
  $=-=int(($-=$_-$B*$i)/($A-$B)+0.999)for@@;
  $a-=$%*($=>=0);
  $%/=2;
  # print"$% $a $i $=$/";
}1..31;
print$i;