#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;
        cin >> s;
        for (auto c : s) {
            if (c == 'G')
                g++;
            else if (c == 'R') {
                g--;
                if (g < 0)
                    break;
            }
        }
        if (g == 0)
            cout << "possible" << endl;
        else
            cout << "impossible" << endl;
    }
    return 0;
}