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)

fn main() {
    let (s, w) = input();
    println!("{}", solve(s, w))
}

fn input() -> (u32, u32) {
    let mut buf = String::new();
    std::io::stdin().read_line(&mut buf).unwrap();
    buf.pop();
    let mut iter = buf.split_whitespace();
    let s: u32 = iter.next().unwrap().parse().unwrap();
    let w: u32 = iter.next().unwrap().parse().unwrap();
    (s, w)
}

fn solve(s: u32, w: u32) -> String {
    if s <= w { return String::from("unsafe"); }
    String::from("safe")
}