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)

N = gets.to_i
A = N.to_s.chars
c = 0
(N.to_s.length - 3).times do |i|
  ((i+3)..N.to_s.length - 1).each do |j|
    num = A[i..j].join.to_i 
    if num >= 200000
      break
    end
    if num % 2019 == 0
      c += 1
    end
  end
end

p c