Problem:
Score : 100 points

Problem Statement

We have a sandglass that runs for X seconds. The sand drops from the upper bulb at a rate of 1 gram per second. That is, the upper bulb initially contains X grams of sand.

How many grams of sand will the upper bulb contains after t seconds?

Constraints

1≤X≤10^9

1≤t≤10^9

X and t are integers.

Input

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

X t

Output

Print the number of sand in the upper bulb after t second.

Sample Input 1

100 17

Sample Output 1

83

17 out of the initial 100 grams of sand will be consumed, resulting in 83 grams.

Sample Input 2

48 58

Sample Output 2

0

All 48 grams of sand will be gone, resulting in 0 grams.

Sample Input 3

1000000000 1000000000

Sample Output 3

0

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

use std::io::*;

fn main() {
    let scan = stdin();

    let mut line = String::new();
    scan.read_line(&mut line).unwrap();

    let token: Vec<&str> = line.split_whitespace().collect();

    let x: i64 = token[0].parse().unwrap();
    let t: i64 = token[1].parse().unwrap();

    if t <= x {
        println!("{}", (x - t));
    } else {
        println!("0");
    }
}