#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

#define RREP(i,s,e) for (i = e-1; i >= s; i--)
#define rrep(i,n) RREP(i,0,n)
#define REP(i,s,e) for (i = s; i < e; i++)
#define rep(i,n) REP(i,0,n)

int main() {
    int i, t;
    cin >> t;
    rep (i,t) {
        string s;
        int g = 0, r = 0, w = 0;
        cin >> s;
        for (auto c : s) {
            if (c == 'G') g++;
            else if (c == 'R') r++;
            else w++;
        }
        if (w >= g && g == r) {
            int bus = 0;
            for (auto c : s) {
                if (c == 'G') {
                    if (bus == 0)
                        break;
                    bus--;
                    g--;
                }
                else if (c == 'R') {
                    if (g == r)
                        break;
                    r--;
                }
                else {
                    if (g == 0)
                        break;
                    bus++;
                    w--;
                }
            }
        }
        if (g == 0 && r == 0 && w == 0)
            cout << "possible" << endl;
        else
            cout << "impossible" << endl;
    }
    return 0;
}