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 Go (1.14.1) (judge verdict: Accepted)

package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var stdInScanner = bufio.NewScanner(os.Stdin)

func nextInt() int {
	stdInScanner.Scan()
	i, _ := strconv.Atoi(stdInScanner.Text())
	return i
}

func main() {
	stdInScanner.Split(bufio.ScanWords)

	S := nextInt()
	W := nextInt()

	if S <= W {
		fmt.Println("unsafe")
	} else {
		fmt.Println("safe")
	}
}