package main

import (
	"bufio"
	"bytes"
	"fmt"
	"os"
	"regexp"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)

func main() {
	sc.Split(bufio.ScanWords)
	t := nextInt()
	r := regexp.MustCompile(`W.*?G`)
	r2 := regexp.MustCompile(`G.*?R`)

	for i := 0; i < t; i++ {
		b := []byte(nextLine())
		c := 0
		for j := 0; j < 3; j++ {
			loc := r.FindIndex(b)
			if loc == nil {
				break
			}

			b[loc[0]] = 'A'
			base := loc[1] - 1

			loc = r2.FindIndex(b[loc[1]-1:])
			if loc == nil {
				break
			}

			b[loc[0]+base], b[loc[1]-1+base] = 'A', 'A'
			c++
		}
		if bytes.Contains(b, []byte{'G'}) || bytes.Contains(b, []byte{'R'}) {
			fmt.Println("impossible")
			continue
		}

		if c < 1 {
			fmt.Println("impossible")
			continue
		}
		fmt.Println("possible")
	}
}

func nextLine() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	i, _ := strconv.Atoi(nextLine())
	return i
}