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 Kotlin (1.3.71) (judge verdict: Accepted)

import java.io.PrintWriter

fun main() {
    val pw = PrintWriter(System.out)

    val (s, w) = readInputLine().split(" ").map { it.toInt() }

    if (w >= s) {
        pw.println("unsafe")
    } else {
        pw.println("safe")
    }

    pw.flush()
}

fun readInputLine(): String {
    return readLine()!!
}