Problem:
Score : 100 points

Problem Statement

There are S sheep and W wolves.

If the number of wolves is greater than or equal to that of sheep, the wolves will attack the sheep.

If the wolves will attack the sheep, print unsafe; otherwise, print safe.

Constraints

1 \leq S \leq 100

1 \leq W \leq 100

Input

Input is given from Standard Input in the following format:

S W

Output

If the wolves will attack the sheep, print unsafe; otherwise, print safe.

Sample Input 1

4 5

Sample Output 1

unsafe

There are four sheep and five wolves. The number of wolves is not less than that of sheep, so they will attack them.

Sample Input 2

100 2

Sample Output 2

safe

Many a sheep drive away two wolves.

Sample Input 3

10 10

Sample Output 3

unsafe

Solution in Rust (1.42.0) (judge verdict: Wrong Answer)

use std::io;
fn main() {
    let mut l1 = String::new();
    let stdin = io::stdin();
    stdin.read_line(&mut l1).unwrap();
    let trimed = l1.trim_end();
    let mut itr = trimed.split_ascii_whitespace();
    let a = itr.next().unwrap();
    let length = a.len();
    if length < 4 {
        println!("{}", 0)
    } else {
        let mut count = 0;
        for i in 0..length - 3 {
            for j in i + 4..length + 1 {
                let num: u128 = a.get(i..j).unwrap().parse().unwrap_or_else(|_x| 0);
                if num != 0 && num % 2019 as u128 == 0 {
                    count = count + 1;
                }
            }
        }
        println!("{}", count);
    }
}