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: import sys
  
  sr = lambda: sys.stdin.readline().rstrip()
  ir = lambda: int(sr())
  lr = lambda: list(map(int, sr().split()))
  from collections import deque
  
  
  def resolve():
      N, M, Q = lr()
      ans = 0
      rest = []
      tmp = 0
      for i in range(Q):
          rest.append(lr())
      rest = deque(sorted(rest, key=lambda x: (x[1], x[0]))[::-1])
      while len(rest) > 0:
          a, b, c, d = rest.popleft()
          Nr = len(rest)
          A = [M] * N
          bi = [0] * N
          tmp = 0
          t = M - c
          r = A[a - 1] - t
          if t >= 1 and r >= 0:
              for j in range(a):
                  A[j] = t
              tmp += d
          bi[b - 1] = -1
          bi[a - 1] = 1
          for i in range(Nr):
              a, b, c, d = rest[i]
              t = A[b - 1] - c
              r = A[a - 1] - t
              if t >= 1 and r >= 0:
                  if not (sum(bi[:a]) and r > 0):
                      bi[b - 1] = -1
                      bi[a - 1] = 1
                      for j in range(a):
                          A[j] -= r
                      tmp += d
          ans = max(tmp, ans)
      print(ans)
  
  
  resolve()
  
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"}]