#include <bits/stdc++.h>

#define REP(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))

using namespace std;

typedef int64_t ll;

const int INF = 1e8;
const double EPS = 1e-10;

int main() {
    ios_base::sync_with_stdio(false);
    string s;
    int n;
    cin >> n;

    while(n--) {
        int r = 0, g = 0, w = 0;
        bool ok = true;
        cin >> s;

        for(int i = 0; i < s.size(); i++) {
            char c = s[i];
            if(c == 'W') {
                w++;
            }
            if(c == 'G') {
                g++;
                if(g > w) {
                    ok = false;
                }
            } 
            if(c == 'R') {
                r++;
                if(r > g) {
                    ok = false;
                }
            }
        }

        if(s.back() != 'R') ok = false;
        if(g > w) ok = false;
        if(r > g) ok = false;

        for(int i = 0; i < s.size(); i++) {
            char c = s[i];
            if(c == 'W') {
                if(r == 0 or g == 0) {
                    ok = false;
                }
                w--;
            }
            if(c == 'G') {
                if(r == 0) {
                    ok = false;
                }
                g--;
            }
            if(c == 'R') {
                r--;
            }
        }

        if(ok) {
            cout << "possible" << endl;
        } else {
            cout << "impossible" << endl;
        }

    }

}