output_description: Among A, B and C, print the integer that is different from the rest.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      A B C
attempt: N, M = map(int, input().split())
  l = [[] for i in range(N)]
  e = [[int(i) for i in input().split()] for i in range(M)]
  e0 = e
  c = 0
  
  
  def DFS(v):
      seen.append(v)
      for v2 in l[v]:
          if not v2 in seen:
              DFS(v2)
      return seen
  
  
  for i in range(M):
      seen = []
      l = [[] for i in range(N)]
      for j in range(M):
          if j != i:
              l[(e[j][0]) - 1].append(e[j][1] - 1)
              l[(e[j][1]) - 1].append(e[j][0] - 1)
      S = DFS(0)
      if len(S) != N:
          c += 1
  print(c)
  
problem_description: Statement
  
  You are given three integers, A, B and C.  
  Among them, two are the same, but the remaining one is different from the
  rest.  
  For example, when A=5,B=7,C=5, A and C are the same, but B is different.  
  Find the one that is different from the rest among the given three integers.
samples: [{"input": "5 7 5", "output": "7\n    \n\nThis is the same case as the one in the statement.\n\n* * *"}, {"input": "1 1 7", "output": "7\n    \n\nIn this case, C is the one we seek.\n\n* * *"}, {"input": "-100 100 100", "output": "-100"}]