output_description: Print the number of ways for the knight to reach (X, Y) from (0, 0), modulo
  10^9 + 7.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      X Y
attempt: x, y = map(int, input().split())
  cnt = 0
  for i in range(0, x + 1):
      for j in range(0, y + 1):
          if (i * 1 + j * 2) == x and (i * 2 + j * 1) == y:
              cnt += 1
  print(cnt * 2)
  
problem_description: Statement
  
  There is a knight - the chess piece - at the origin (0, 0) of a two-
  dimensional grid.
  
  When the knight is at the square (i, j), it can be moved to either (i+1,j+2)
  or (i+2, j+1).
  
  In how many ways can the knight reach the square (X, Y)?
  
  Find the number of ways modulo 10^9 + 7.
samples: [{"input": "3 3", "output": "2\n    \n\nThere are two ways: (0,0) \\to (1,2) \\to (3,3) and (0,0) \\to (2,1) \\to (3,3).\n\n* * *"}, {"input": "2 2", "output": "0\n    \n\nThe knight cannot reach (2,2).\n\n* * *"}, {"input": "999999 999999", "output": "151840682\n    \n\nPrint the number of ways modulo 10^9 + 7."}]