#include <bits/stdc++.h>
using namespace std;

int main() {
    int n; cin >> n;
    for (int ni = 0; ni < n; ni++) {
        string s; cin >> s;
        bool ans = true;
        int rcount = 0; int gcount = 0;
        int wrequire = 0; bool wflag = false;
        for (int i = s.size()-1; i >= 0; i--) {
            if (s[i] == 'R') rcount++;
            if (s[i] == 'G') gcount++;
            if (rcount < gcount) ans *= false;
            if (rcount > 0 && gcount > 0) {
                wrequire++; wflag = true;
                rcount--; gcount--;
            }
            if (s[i] == 'W') {
                if (!wflag) ans *= false;
                else {
                    wrequire = max(wrequire-1, 0);
                }
            }
        }
        if (!wflag || wrequire > 0 || rcount > 0 || gcount > 0) ans *= false;
        if (ans) cout << "possible" << endl;
        else cout << "impossible" << endl;
    }
    return 0;
}