Problem:
Score : 100 points

Problem Statement

Joisino wants to evaluate the formula "A op B".
Here, A and B are integers, and the binary operator op is either + or -.
Your task is to evaluate the formula instead of her.

Constraints

1≦A,B≦10^9

op is either + or -.

Input

The input is given from Standard Input in the following format:

A op B

Output

Evaluate the formula and print the result.

Sample Input 1

1 + 2

Sample Output 1

3

Since 1 + 2 = 3, the output should be 3.

Sample Input 2

5 - 7

Sample Output 2

-2

Solution in Rust (1.15.1) (judge verdict: Accepted)

use std::io::stdin;

#[allow(dead_code)]
fn input_ints() -> Vec<i32> {
    let mut st = String::new();
    match stdin().read_line(&mut st) {
        Ok(_) => st.split_whitespace().map(|s| s.parse().unwrap()).collect(),
        Err(_) => "".split_whitespace().map(|s| s.parse().unwrap()).collect(),
    }
}

#[allow(dead_code)]
fn input_strs() -> Vec<String> {
    let mut st = String::new();
    match stdin().read_line(&mut st) {
        Ok(_) => st.split_whitespace().map(|s| s.to_string()).collect(),
        Err(_) => "".split_whitespace().map(|s| s.to_string()).collect(),
    }
}

fn main() {
    let line = input_strs();
    // let line = input_ints().to_array();
    let x: i32 = (&line[0]).parse().unwrap();
    let op = &line[1];
    let y: i32 = (&line[2]).parse().unwrap();

    if op == "+" {
        println!("{}",x + y);
    }
    else {
        println!("{}",x - y);
    } 
}