output_description: Print a positive integer not greater than 10^{18} that is a multiple of X but
  not a multiple of Y, or print -1 if it does not exist.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      X Y
attempt: N = int(input())
  A, B = [sorted(map(int, input().split())) for _ in range(2)]
  print("Yes" if all([a <= b for a, b in zip(A, B)]) else "No")
  
problem_description: Statement
  
  You are given positive integers X and Y. If there exists a positive integer
  not greater than 10^{18} that is a multiple of X but not a multiple of Y,
  choose one such integer and print it. If it does not exist, print -1.
samples: [{"input": "8 6", "output": "16\n    \n\nFor example, 16 is a multiple of 8 but not a multiple of 6.\n\n* * *"}, {"input": "3 3", "output": "-1\n    \n\nA multiple of 3 is a multiple of 3."}]