output_description: Print the probability that a is odd. Your output will be considered correct
  when its absolute or relative error from the judge's output is at most
  10^{-6}.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
attempt: N, M = map(int, input().split())
  a = []
  for i in range(M):
      tmp = list(map(int, input().split()))
      tmpc = list(map(int, input().split()))
      c = 0
      for j in range(len(tmpc)):
          c += 2 ** (tmpc[j] - 1)
      tmp[1] = c
      a += [tmp]
  
  
  dp = [[10**10 for j in range(2**N)] for i in range(M)]
  dp[0][0] = 0
  dp[0][a[0][1]] = a[0][0]
  
  
  for i in range(1, M):
      dp[i] = dp[i - 1]
      for j in range(2**N):
          if dp[i - 1][j] < 10**10:
              q = j | a[i][1]
              dp[i][q] = min(dp[i - 1][j] + a[i][0], dp[i][q])
  
  ans = dp[M - 1][2**N - 1]
  print(ans if ans < 10**10 else -1)
  
problem_description: Statement
  
  Given is an integer N.
  
  Takahashi chooses an integer a from the positive integers not greater than N
  with equal probability.
  
  Find the probability that a is odd.
samples: [{"input": "4", "output": "0.5000000000\n    \n\nThere are four positive integers not greater than 4: 1, 2, 3, and 4. Among\nthem, we have two odd numbers: 1 and 3. Thus, the answer is \\frac{2}{4} = 0.5.\n\n* * *"}, {"input": "5", "output": "0.6000000000\n    \n\n* * *"}, {"input": "1", "output": "1.0000000000"}]