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

        std::io::stdin().read_line(&mut buf).unwrap();
        let mut iter = buf.split_whitespace();
        let a: i32 = iter.next().unwrap().parse().unwrap();
        let op: String = iter.next().unwrap().parse().unwrap();
        let b: i32 = iter.next().unwrap().parse().unwrap();

    let ans = if  op == "+" { a+b } else { a-b };
    println!("{}",ans);
}