from typing_extensions import Annotated
T=int(input())
S=[list(input()) for _ in range(T)]


for i in range(T):
  w=g=r=0
  t=True
  for j in range(len(S[i])):
    if not w>=g>=r:
      print("imporssible")
      t=False
      break
    if S[i][j]=="W":
      w+=1
    if S[i][j]=="G":
      g+=1
    if S[i][j]=="R":
      r+=1
  if g==r and t:
    print("possible")
  else:
    print("impossible")