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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