package main

import (
	"fmt"
)

func check(s string) bool {
	R := 0
	G := 0
	W := 0
	for i := len(s) - 1; i >= 0; i-- {
		switch s[i] {
		case 'R':
			R++
		case 'G':
			if 0 < R {
				R--
				G++
			} else {
				return false
			}
		case 'W':
			if 0 < G {
				G--
			} else if 0 == W {
				return false
			}
			W++
		}
	}
	return R == 0 && G == 0
}
func main() {
	var N int
	fmt.Scanf("%d", &N)
	for i := 0; i < N; i++ {
		var s string
		fmt.Scanf("%s", &s)
		if check(s) {
			fmt.Println("possible")
		} else {
			fmt.Println("impossible")
		}
	}
}