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 Python (3.8.2) (judge verdict: Runtime Error)

def judge(s,w):
  print("羊の数を入力してください：")
  s = input()
  int_s = int(s)
  if s < 0 or s > 100:
    print("1から100の間でお願いします")
    continue
  else:
    break
  print("次に狼の数を入力してください：")
  w = input()
  int_w = int(w)
  if w < 0 or w > 1000:
    print("1から1000の間でお願いします")
    continue
  else:
    break

if int_s > int_w:
  print("safe")
else:
  print("unsafe")
  
judge()