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)

#![allow(unused_macros)]

macro_rules! line {
    () => {{
        let mut buf = String::new();
        std::io::stdin().read_line(&mut buf).unwrap();
        buf
    }};
}
macro_rules! line_as_vec {
    ( $t:ty ) => {
        line!()
            .trim()
            .split_whitespace()
            .map(|x| x.parse().unwrap())
            .collect::<Vec<$t>>()
    };
}
macro_rules! input {
    { $( $i:ident : $t:ty ),* } => {
        let ( $( $i ),* ) = match &line!().split_whitespace().collect::<Vec<_>>()[..] {
            &[ $( $i ),* ] => ( $( $i.parse::<$t>().unwrap() ),* ),
            _ => panic!(),
        };
    };
}

fn main() {
    input!(s: i8, w: i8);
    println!("{}safe", if s > w { "" } else { "un" })
}