output_description: Print the maximum possible score of A.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N M Q
      a_1 b_1 c_1 d_1
      :
      a_Q b_Q c_Q d_Q
attempt: N, N, Q = map(int, input().split())
  abcd = [list(map(int, input().split())) for i in range(Q)]
  
  abcd.sort()
  total = 0
  
  for i in range(2**Q):
      now = str(format(i, "b")).zfill(Q)
      A = [-1] * N
      flag = 0
      tmp = 0
      for j in range(Q):
          if now[j] == "1":
              mi = abcd[j][0] - 1
              ma = abcd[j][1] - 1
              if A[mi] == -1:
                  A[mi] = 0
              if A[ma] == -1:
                  A[ma] = A[mi] + abcd[j][2]
              elif A[ma] != A[mi] + abcd[j][2]:
                  flag = 1
                  break
              tmp += abcd[j][3]
      if tmp > total:
          total = tmp
  print(total)
  
problem_description: Statement
  
  Given are positive integers N, M, Q, and Q quadruples of integers ( a_i , b_i
  , c_i , d_i ).
  
  Consider a sequence A satisfying the following conditions:
  
    * A is a sequence of N positive integers.
    * 1 \leq A_1 \leq A_2 \le \cdots \leq A_N \leq M.
  
  Let us define a score of this sequence as follows:
  
    * The score is the sum of d_i over all indices i such that A_{b_i} - A_{a_i} = c_i. (If there is no such i, the score is 0.)
  
  Find the maximum possible score of A.
samples: [{"input": "3 4 3\n    1 3 3 100\n    1 2 2 10\n    2 3 2 10", "output": "110\n    \n\nWhen A = \\\\{1, 3, 4\\\\}, its score is 110. Under these conditions, no sequence\nhas a score greater than 110, so the answer is 110.\n\n* * *"}, {"input": "4 6 10\n    2 4 1 86568\n    1 4 0 90629\n    2 3 0 90310\n    3 4 1 29211\n    3 4 3 78537\n    3 4 2 8580\n    1 2 1 96263\n    1 4 2 2156\n    1 2 0 94325\n    1 4 3 94328", "output": "357500\n    \n\n* * *"}, {"input": "10 10 1\n    1 10 9 1", "output": "1"}]