output_description: Print the largest value among A+B, A-B and A \times B.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      A B
attempt: N = int(input())
  S = input()
  temp = 0
  for i in range(N - 1):
      S1 = S[0 : i + 1]
      S2 = S[i + 1 : N]
      #    print(S1 + " " + S2)
      kaburi = []
      for s in S1:
          if s in S2 and s not in kaburi:
              kaburi.append(s)
      print(kaburi)
      if len(kaburi) > temp:
          temp = len(kaburi)
  print(temp)
  
problem_description: Statement
  
  You are given two integers A and B. Find the largest value among A+B, A-B and
  A \times B.
samples: [{"input": "3 1", "output": "4\n    \n\n3+1=4, 3-1=2 and 3 \\times 1=3. The largest among them is 4.\n\n* * *"}, {"input": "4 -2", "output": "6\n    \n\nThe largest is 4 - (-2) = 6.\n\n* * *"}, {"input": "0 0", "output": "0"}]