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"
	"strings"
)

func main() {
	sc.Split(bufio.ScanWords)
	var S, W int
	nextInt(&S, &W)
	if W >= S {
		fmt.Printf("unsafe")
	} else {
		fmt.Printf("safe")
	}
}

const MAX_INT int = 1_000_000_000

var sc = bufio.NewScanner(os.Stdin)

var reader = bufio.NewReaderSize(os.Stdin, 1000000)
var writer = bufio.NewWriter(os.Stdout)

func nextLine() string {
	buffer := make([]byte, 0)
	for true {
		line, isPrefix, err := reader.ReadLine()
		if err != nil {
			panic(err)
		}
		buffer = append(buffer, line...)
		if !isPrefix {
			break
		}
	}
	return string(buffer)
}

func nextInt(A ...*int) {
	L := strings.Split(nextLine(), " ")
	for i, a := range A {
		*a, _ = strconv.Atoi(L[i])
	}
}
func nextInts(A *[]int) {
	L := strings.Split(nextLine(), " ")
	(*A) = make([]int, len(L))
	for i, l := range L {
		(*A)[i], _ = strconv.Atoi(l)
	}
}

func nextInt64(A ...*int64) {
	L := strings.Split(nextLine(), " ")
	for i, a := range A {
		*a, _ = strconv.ParseInt(L[i], 0, 64)
	}
}

func max(a int, b int) int {
	if a >= b {
		return a
	}
	return b
}