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

int main() {
    int T;
    cin >> T;

    while (T--) {
        string S;
        cin >> S;

        bool flag = true;
        int cnt[1010] = {};
        bool flag2 = false;

        for (int i = S.size() - 1; i >= 0; i--) {
            char c = S[i];
            if (c == 'W')
                if (!flag2)
                    flag = false;
                else if (cnt[1])
                    cnt[1]--, cnt[0]++;
            if (c == 'G')
                if (cnt[2] == 0)
                    flag = false;
                else
                    cnt[2]--, cnt[1]++, flag2 = 1;
            if (c == 'R')
                cnt[2]++;
        }
        if (cnt[1] || cnt[2])
            flag = false;
        cout << (flag ? "" : "im") << "possible" << endl;
    }
}