/* -*- coding: utf-8 -*-
 *
 * 154.cc: No.154 市バス - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

/* typedef */

/* global variables */

/* subroutines */

/* main */

int main() {
  int tn;
  cin >> tn;

  while (tn--) {
    string s;
    cin >> s;

    bool ok = true, gf = false;
    int r = 0, g = 0;

    for (int i = s.size() - 1; i >= 0; i--) {
      if (s[i] == 'R')
	r++;
      else if (s[i] == 'G') {
	if (r == 0) {
	  ok = false;
	  break;
	}
	r--, g++, gf = true;
      }
      else if (s[i] == 'W') {
	if (! gf) {
	  ok = false;
	  break;
	}
	if (g > 0) g--;
      }
    }

    if (r > 0 || g > 0) ok = false;
    cout << (ok ? "possible" : "impossible") << endl;
  }

  return 0;
}