#include <bits/stdc++.h>

using namespace std;

int main() {
  int t;
  cin >> t;
  for (int i = 0; i < t; ++i) {
    string s;
    cin >> s;
    reverse(s.begin(), s.end());
    while (s.back() == 'W') s.pop_back();
    int a = 0, b = 0, c = 0;
    bool p = true;
    for (char t : s) {
      if (t == 'W') ++a;
      if (t == 'G') ++b;
      if (t == 'R') ++c;
      if (a > b) p = false;
      if (b > c) p = false;
    }
    if (b != c) p = false;
    cout << (p ? "possible" : "impossible") << endl;
  }
}