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"
)

const (
	initialBufSize = 1024
	maxBufSize     = 1e6
)

var (
	scanner = bufio.NewScanner(os.Stdin)
	// writer  = bufio.NewWriterSize(os.Stdout, 1000000)
)

func main() {
	scanner.Split(bufio.ScanWords)
	// scanner.Buffer(make([]byte, initialBufSize), maxBufSize)
	// defer writer.Flush()
	s, w := scanInt(), scanInt()
	if w >= s {
		fmt.Println("unsafe")
	} else {
		fmt.Println("safe")
	}
}

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

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

func scanFloat64() float64 {
	f, _ := strconv.ParseFloat(scanString(), 64)
	return f
}

func scanFloat64s(size int) []float64 {
	f := make([]float64, size)
	for i := 0; i < size; i++ {
		f[i] = scanFloat64()
	}
	return f
}

func scanString() string {
	scanner.Scan()
	return scanner.Text()
}

func scanStrings(size int) []string {
	s := make([]string, size)
	for i := 0; i < size; i++ {
		s[i] = scanString()
	}
	return s
}