t=int(input())
sary=[list(input()) for _ in range(t)]
from collections import Counter
for s in sary:
  cs=dict(Counter(s))
  if "W" not in cs or "G" not in cs or "R" not in cs:
    print("impossible")
    continue
  if cs["R"]!=cs["G"] or cs["R"]>cs["W"]:
    print("impossible")
    continue
  flg=True
  counter={"W":0,"G":0,"R":0}
  for x in s:
    counter[x]+=1
    if counter["W"]>=counter["G"]>=counter["R"]:
      pass
    else:
      flg=False
      break
    if counter["G"]==cs["G"] and x=="W":
      flg=False
      break
  if flg:
    print("possible")
  else:
    print("impossible")