output_description: Find the number of the non-empty contiguous subsequences of A whose sum is 0.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
      A_1 A_2 ... A_N
attempt: N=int(input())
  A=list(map(int,input().split())
  B=[0]
  for i in range(N):
    B+=[B[i]+A[i]]
  C=[]
  asn+=1      
  for i in B:
    if i in C:
       ans+=1
    else:
       C+=[i]
  print(ans)
problem_description: Statement
  
  We have an integer sequence A, whose length is N.
  
  Find the number of the non-empty **contiguous** subsequences of A whose sums
  are 0. Note that we are counting **the ways to take out subsequences**. That
  is, even if the contents of some two subsequences are the same, they are
  counted individually if they are taken from different positions.
samples: [{"input": "6\n    1 3 -4 2 2 -2", "output": "3\n    \n\nThere are three contiguous subsequences whose sums are 0: (1,3,-4), (-4,2,2)\nand (2,-2).\n\n* * *"}, {"input": "7\n    1 -1 1 -1 1 -1 1", "output": "12\n    \n\nIn this case, some subsequences that have the same contents but are taken from\ndifferent positions are counted individually. For example, three occurrences\nof (1, -1) are counted.\n\n* * *"}, {"input": "5\n    1 -2 3 -4 5", "output": "0\n    \n\nThere are no contiguous subsequences whose sums are 0."}]