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: Accepted)

#![allow(unused_imports)]
use std::io;
use std::cmp::*;
use std::collections::HashMap;
#[allow(dead_code)]
const M: i64 = 1e9 as i64 + 7;

fn read_line() -> String {
    let stdin = io::stdin();
    let mut buf = String::new();
    stdin.read_line(&mut buf).unwrap();
    buf
}
#[allow(dead_code)]
fn read<T>() -> T where T: std::str::FromStr, T::Err : std::fmt::Debug {
    read_line().trim().parse().unwrap()
}
#[allow(dead_code)]
fn readv<T>() -> Vec<T> where T: std::str::FromStr, T::Err : std::fmt::Debug {
    read_line().split(' ').map(|a| a.trim().parse().unwrap()).collect()
}

fn main() {
    let input = readv::<i32>();
    let (a, b) = (input[0], input[1]);
    if a + b >= 10 {
        println!("{}", "error");
    } else {
        println!("{}", a + b);
    }
}