output_description: Print the shortest distance in a line. If there is no solution, print -1.
input_description: |V| |E|
      s0 t0 d0
      s1 t1 d1
      :
      s|E|-1 t|E|-1 d|E|-1
      
  
  |V| is the number of vertices and |E| is the number of edges in the graph. The
  graph vertices are named with the numbers 0, 1,..., |V|-1 respectively.
  
  si and ti represent source and target vertices of i-th edge (directed) and di
  represents the distance between si and ti (the i-th edge).
attempt: from sys import stdin
  from sys import setrecursionlimit
  
  setrecursionlimit(10**9)
  
  readline = stdin.readline
  n, w = map(int, readline().split())
  INF = 10**9
  G = [[INF] * n for _ in range(n)]
  
  for _ in range(w):
      s, t, d = map(int, readline().split())
      G[s][t] = d
  
  dp = [[-1] * n for _ in range(1 << n)]
  
  
  def func(s, v):
      if dp[s][v] >= 0:
          return dp[s][v]
  
      if (s == (1 << n) - 1) and v == 0:
          dp[s][v] = 0
          return dp[s][v]
  
      tmp = INF
      for u in range(n):
          t = (1 << u) | s
          if t == s:
              continue
          tmp = min(tmp, func(t, u) + G[v][u])
      dp[s][v] = tmp
      return dp[s][v]
  
  
  ans = func(0, 0)
  print(ans if ans < INF else -1)
  
problem_description: Traveling Salesman Problem
  
    
  
  For a given weighted directed graph G(V, E), find the distance of the shortest
  route that meets the following criteria:
  
    * It is a closed cycle where it ends at the same point it starts.
    * It visits each vertex exactly once.
samples: [{"input": "4 6\n    0 1 2\n    1 2 3\n    1 3 9\n    2 0 1\n    2 3 6\n    3 2 4", "output": "16"}, {"input": "3 3\n    0 1 1\n    1 2 1\n    0 2 1", "output": "-1"}]