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;
use std::str::FromStr;

fn main() {
    let vec: Vec<u32> = read_split_line();
    if vec[0] > vec[1] {
        println!("{}", "safe");
    } else {
        println!("{}", "unsafe");
    }
}

#[allow(dead_code)]
fn read_elem<T: FromStr>() -> T {
    let mut l = String::new();
    stdin().read_line(&mut l).unwrap();
    l.trim().parse().ok().unwrap()
}

#[allow(dead_code)]
fn read_n_elems<T: FromStr>() -> Vec<T> {
    let n = read_elem::<u32>();
    let mut vec: Vec<T> = vec![];
    for _i in 0..n {
        vec.push(read_elem::<T>());
    }
    vec
}

#[allow(dead_code)]
fn read_split_line<T: FromStr>() -> Vec<T> {
    let mut l = String::new();
    stdin().read_line(&mut l).unwrap();
    l.trim().split_whitespace().map(|e| e.parse().ok().unwrap()).collect()
}