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: Accepted)

use std::io::stdin;
fn read() -> (i32, i32) {
    let mut s = String::new();
    stdin().read_line(&mut s).unwrap();
    let vec: Vec<i32> = s
        .trim()
        .split_whitespace()
        .map(|x| x.parse().unwrap())
        .collect();
    (vec[0], vec[1])
}

fn main() {
    let (a, b) = read();
    if a > b {
        println!("safe")
    } else {
        println!("unsafe")
    }
}