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"
)

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

func scanInt64() int64 {
	sc.Scan()
	i, _ := strconv.ParseInt(sc.Text(), 10, 64)
	return i
}

func scanInts(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = scanInt()
	}
	return res
}

func scanInts64(n int) []int64 {
	res := make([]int64, n)
	for i := range res {
		res[i] = scanInt64()
	}
	return res
}

var sc = bufio.NewScanner(os.Stdin)

func main() {
	sc.Split(bufio.ScanWords)
	s, w := scanInt(), scanInt()

	if s <= w {
		fmt.Println("unsafe")
	} else {
		fmt.Println("safe")
	}
}