output_description: Print the answer.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      S
attempt: N = int(input())
  a = [0 for _ in range(2001)]
  a[:10] = [0, 0, 0, 1, 1, 1, 2, 3, 4, 4]
  for i in range(10, 2001):
      b = 0
      for j in range(3, 10):
          if (i - j) >= 3:
              b += a[i - j] * a[j] % (10**9 + 7)
      a[i] = b % (10**9 + 7)
  print(a[N % (10**9 + 7)])
  
problem_description: Statement
  
  Given is an integer S. Find how many sequences there are whose terms are all
  integers greater than or equal to 3, and whose sum is equal to S. The answer
  can be very large, so output it modulo 10^9 + 7.
samples: [{"input": "7", "output": "3\n    \n\n3 sequences satisfy the condition: \\\\{3,4\\\\}, \\\\{4,3\\\\} and \\\\{7\\\\}.\n\n* * *"}, {"input": "2", "output": "0\n    \n\nThere are no sequences that satisfy the condition.\n\n* * *"}, {"input": "1729", "output": "294867501"}]