#include <bits/stdc++.h>

using namespace std;

int main() {
  int t;
  cin >> t;
  for (int i = 0; i < t; ++i) {
    string s;
    cin >> s;
    int a = 0;
    bool p = true;
    for (char c : s) {
      if (c == 'G') ++a;
      if (c == 'R') {
        --a;
        if (a < 0) p = false;
      }
    }
    if (a) p = false;
    cout << (p ? "possible" : "impossible") << endl;
  }
}