from collections import *
from heapq import *
import sys

sys.setrecursionlimit(10 ** 6)
int1 = lambda x: int(x) - 1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.readline())
def MI(): return map(int, sys.stdin.readline().split())
def MF(): return map(float, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LF(): return list(map(float, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]

def main():
    t=II()
    for _ in range(t):
        s=input()
        cw=cg=cr=0
        for c in s:
            if c=="W":
                cw+=1
            if c=="G":
                cg+=1
                if cg>cw:
                    print("impossible")
                    break
            if c=="R":
                cr+=1
                if cr>cg or cr>cw:
                    print("impossible")
                    break
        else:
            if cr==cg:
                print("possible")
            else:
                print("impossible")

main()