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 Ruby (2.7.1) (judge verdict: Wrong Answer)

CV = 2019
  s = gets.strip.chars.map(&:to_i)
  c = 0

  sz = s.size
  0.upto(sz-4) do |i|
    (i+3).upto(sz-1) do |j|
      c += 1  if s[i..j].map(&:to_s).join.to_i % CV == 0
    end
  end
  p c