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)

struct Rin{}
impl Rin{
    fn input(&self)->String{
        let mut x=String::new();
        std::io::stdin().read_line(&mut x).ok();
        x
    }
    fn inputs(&self)->String{
        let s=self.input().trim().to_string();
        s
    }
    fn inputn(&self)->i32{
        let n:i32=self.input().trim().parse().unwrap();
        n
    }
    fn inputvs(&self)->Vec<String>{
        let vs=self.input().trim().split(' ').map(|x|x.to_string()).collect();
        vs
    }
    fn inputvn(&self)->Vec<i32>{
        let vn=self.input().trim().split(' ').map(|x|x.to_string().parse().unwrap()).collect();
        vn
    }
}

fn main(){
    let rin=Rin{};
    let v=rin.inputvn();
    let s=v[0];
    let w=v[1];
    if s<=w{
        println!("unsafe");
    }else{
        println!("safe");
    }
}