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::error::Error;
use std::io;
use std::str::FromStr;

fn get_line() -> io::Result<String> {
	let mut buffer = String::new();
	io::stdin().read_line(&mut buffer)?;
	Ok(buffer)
}

#[allow(dead_code)]
fn get_input_number<T>() -> Result<T, Box<dyn Error + 'static>>
where
	T: FromStr,
	<T as FromStr>::Err: Error + 'static,
{
	Ok(get_line()?.trim().parse::<T>()?)
}

#[allow(dead_code)]
fn get_input_array<T>() -> Result<Vec<T>, Box<dyn Error + 'static>>
where
	T: FromStr,
	<T as FromStr>::Err: Error + 'static,
{
	Ok(get_line()?
		.split_whitespace()
		.map(|s| s.parse::<T>())
		.collect::<Result<Vec<_>, _>>()?)
}

fn main() -> Result<(), Box<dyn Error>> {
	let input = get_input_array::<u8>()?;
	if input[0] > input[1] {
		println!("{}", "safe");
	} else {
		println!("{}", "unsafe");
	}
	Ok(())
}