output_description: Print the number of strings of length N that satisfy the following conditions,
  modulo 10^9+7.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
attempt: A = [0, 1, 4]
  G = [0, 1, 4]
  C = [0, 1, 4]
  T = [0, 1, 4]
  AG = [0, 0, 1]
  GA = [0, 0, 1]
  AC = [0, 0, 1]
  AT = [0, 0, 1]
  AGG = [0, 0, 0]
  ATG = [0, 0, 0]
  AGT = [0, 0, 0]
  for i in range(2, 100):
      A.append(A[i] + G[i] + C[i] + T[i])
      G.append(A[i] + G[i] + C[i] + T[i] - AC[i])
      C.append(A[i] + G[i] + C[i] + T[i] - AG[i] - GA[i] - AGG[i] - ATG[i] - AGT[i])
      T.append(A[i] + G[i] + C[i] + T[i])
      AG.append(A[i])
      GA.append(G[i])
      AC.append(A[i] - GA[i])
      AT.append(A[i])
      AGG.append(AG[i])
      ATG.append(AT[i])
      AGT.append(AG[i])
  N = int(input())
  print((A[N] + G[N] + C[N] + T[N]) % (10**9 + 7))
  
problem_description: Statement
  
  You are given an integer N. Find the number of strings of length N that
  satisfy the following conditions, modulo 10^9+7:
  
    * The string does not contain characters other than `A`, `C`, `G` and `T`.
    * The string does not contain `AGC` as a substring.
    * The condition above cannot be violated by swapping two adjacent characters once.
samples: [{"input": "3", "output": "61\n    \n\nThere are 4^3 = 64 strings of length 3 that do not contain characters other\nthan `A`, `C`, `G` and `T`. Among them, only `AGC`, `ACG` and `GAC` violate\nthe condition, so the answer is 64 - 3 = 61.\n\n* * *"}, {"input": "4", "output": "230\n    \n\n* * *"}, {"input": "100", "output": "388130742\n    \n\nBe sure to print the number of strings modulo 10^9+7."}]