#include<iostream>
#include<string>
#include<regex>
using namespace std;

string solve(string str){
    # define OK "possible"
    # define NG "impossible"
    regex re("^W+");
    reverse(str.begin(), str.end());
    while(!str.empty()){
        if(str[0] != 'R') return NG;
        str.replace(0, 1, "");
        int g_index = str.find("G");
        if(g_index == -1) return NG;
        str.replace(g_index, 1, "");
        int w_index = str.find("W");
        if(w_index == -1) return NG;
        str.replace(w_index, 1, "");
        str = regex_replace(str, re, "",
        regex_constants::format_first_only);
    }
    return OK;

}

int main(){
	int n;
	cin >> n;
	for(int i=0; i<n; ++i){
		string str;
		cin >> str;
        cout << solve(str) << endl;
	}
}