#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());
        bool ok = true;
        int r = 0;
        for (char c : s) {
            if (c == 'R') {
                r++;
            } else if (c == 'G') {
                r--;
                if (r < 0) {
                    ok = false;
                    break;
                }
            }
        }
        if (r) ok = false;
        if (ok) {
            puts("possible");
        } else {
            puts("impossible");
        }
    }
}