output_description: If the wolves will attack the sheep, print `unsafe`; otherwise, print `safe`.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      S W
attempt: print("safe")
  
problem_description: 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`.
samples: [{"input": "4 5", "output": "unsafe\n    \n\nThere are four sheep and five wolves. The number of wolves is not less than\nthat of sheep, so they will attack them.\n\n* * *"}, {"input": "100 2", "output": "safe\n    \n\nMany a sheep drive away two wolves.\n\n* * *"}, {"input": "10 10", "output": "unsafe"}]