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: Wrong Answer)

fn main() {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).unwrap();

    let mut a = 0;
    for _i in s.trim().chars() {
        if a % 2 == 0 { 
            print!("{}", _i);
        }
        a += 1;
    }   
    println!("");
}