#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

int main(){
  int T; cin >> T;
  for(int i = 0; i < T; i++){
    string S; cin >> S;
    int s = (int)S.size();
    int W = 0, G = 0, R = 0;
    bool flag = true;
    for(int j = 0; j < s; j++){
      switch(S[j]){
        case 'W': 
          W++; 
          break;
        case 'G': 
          W = 0; 
          G++; 
          break;
        case 'R': 
          W = 0; 
          R++;
          if(G < R) flag = false;
          break;
      }
    }
    if(flag and W == 0 and G == R) cout << "possible" << endl;
    else cout << "impossible" << endl;
  }
}