#include<bits/stdc++.h>
using namespace std;
#ifdef LOCAL_DEBUG
  #include "LOCAL_DEBUG.hpp"
#endif
#define int long long

signed main(){

  int n; cin >> n;
  for(int i = 0; i < n; i++){
    string s; cin >> s;
    map<char, int> mp;
    mp['W'] = 0, mp['G'] = 0, mp['R'] = 0;
    bool judge = true;
    for(int j = 0; j < s.size(); j++){
      if(s[j] == 'R'){
        if(mp['G'] == mp['R']){
          judge = false;
        }else{
          mp['R']++;
        }
      }
      if(s[j] == 'G'){
        mp['G']++;
        if(mp['W'] == 0){
          judge = false;
        }else{
          mp['W']--;
        }
      }
      if(s[j] == 'W'){
        mp['W']++;
      }
    }
    if(judge && mp['G'] == mp['R'] && mp['G'] != 0){
      cout << "possible" << endl;
    }else{
      cout << "impossible" << endl;
    }
  }

  return 0;
}