output_description: If it is possible to give cookies so that each of the three goats can have the
  same number of cookies, print `Possible`; otherwise, print `Impossible`.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      A B
attempt: import sys
  import math
  import collections
  import itertools
  import array
  import inspect
  
  # Set max recursion limit
  sys.setrecursionlimit(1000000)
  
  
  # Debug output
  def chkprint(*args):
      names = {id(v): k for k, v in inspect.currentframe().f_back.f_locals.items()}
      print(", ".join(names.get(id(arg), "???") + " = " + repr(arg) for arg in args))
  
  
  # Binary converter
  def to_bin(x):
      return bin(x)[2:]
  
  
  def li_input():
      return [int(_) for _ in input().split()]
  
  
  def gcd(n, m):
      if n % m == 0:
          return m
      else:
          return gcd(m, n % m)
  
  
  def gcd_list(L):
      v = L[0]
  
      for i in range(1, len(L)):
          v = gcd(v, L[i])
  
      return v
  
  
  def lcm(n, m):
      return (n * m) // gcd(n, m)
  
  
  def lcm_list(L):
      v = L[0]
  
      for i in range(1, len(L)):
          v = lcm(v, L[i])
  
      return v
  
  
  # Width First Search (+ Distance)
  def wfs_d(D, N, K):
      """
      D: 隣接行列(距離付き)
      N: ノード数
      K: 始点ノード
      """
  
      dfk = [-1] * (N + 1)
      dfk[K] = 0
  
      cps = [(K, 0)]
      r = [False] * (N + 1)
      r[K] = True
      while len(cps) != 0:
          n_cps = []
          for cp, cd in cps:
              for i, dfcp in enumerate(D[cp]):
                  if dfcp != -1 and not r[i]:
                      dfk[i] = cd + dfcp
                      n_cps.append((i, cd + dfcp))
                      r[i] = True
  
          cps = n_cps[:]
  
      return dfk
  
  
  # Depth First Search (+Distance)
  def dfs_d(v, pre, dist):
      """
      v:  現在のノード
      pre: １つ前のノード
      dist: 現在の距離
  
      以下は別途用意する
      D: 隣接リスト(行列ではない)
      D_dfs_d: dfs_d関数で用いる，始点ノードから見た距離リスト
      """
  
      global D
      global D_dfs_d
  
      D_dfs_d[v] = dist
  
      for next_v, d in D[v]:
          if next_v != pre:
              dfs_d(next_v, v, dist + d)
  
      return
  
  
  # --------------------------------------------
  
  dp = None
  
  
  def main():
      A, B = li_input()
  
      if A % 3 == 0 or B % 3 == 0 or (A + B) % 3 == 0:
          print("Possible")
      else:
          print("Impossible")
  
  
  main()
  
problem_description: Statement
  
  Snuke is giving cookies to his three goats.
  
  He has two cookie tins. One contains A cookies, and the other contains B
  cookies. He can thus give A cookies, B cookies or A+B cookies to his goats (he
  cannot open the tins).
  
  Your task is to determine whether Snuke can give cookies to his three goats so
  that each of them can have the same number of cookies.
samples: [{"input": "4 5", "output": "Possible\n    \n\nIf Snuke gives nine cookies, each of the three goats can have three cookies.\n\n* * *"}, {"input": "1 1", "output": "Impossible\n    \n\nSince there are only two cookies, the three goats cannot have the same number\nof cookies no matter what Snuke gives to them."}]