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 Rust (1.15.1) (judge verdict: Runtime Error)

use std::io::prelude::*;
use std::io;

fn main() {
    let mut stdin = io::stdin();
    let mut buf = String::new();

    stdin.read_to_string(&mut buf).unwrap();
    
    let mut buf = buf.split(' ');

    let (a, b) = {
        let a: i32 = buf.next().unwrap().parse().unwrap();
        let b: i32 = buf.next().unwrap().parse().unwrap();
        (a, b)
    };
    
    if a + b < 10 {
        println!("{}", a + b);
    } else {
        println!("error");
    }

}