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 PyPy3 (7.3.0) (judge verdict: Accepted)

#!/usr/bin/env python3
# Generated by https://github.com/kyuridenamida/atcoder-tools
import sys

INF = 1145141919


def solve(S: int, W: int):
    return 'unsafe' if W >= S else 'safe'


def main():

    sys.setrecursionlimit(10 ** 6)

    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    S = int(next(tokens))  # type: int
    W = int(next(tokens))  # type: int
    print(solve(S, W))


if __name__ == '__main__':
    main()