#include <iostream>
#include <string>

int main()
{
    int T;
    std::cin >> T;
    for (int i = 0; i < T; ++i) {
        std::string S;
        std::cin >> S;
        int W = 0;
        int G = 0;
        int R = 0;
        bool ng = false;
        bool l = false;
        for (auto c : S) {
            if (c == 'W') {
                ++W;
                l = true;
            } else if (c == 'G') {
                ++G;
                l = false;
                ng = G > W;
            } else {
                ++R;
                ng = R > G;
            }
            if (ng) {
                break;
            }
        }
        ng = ng || G != R || l;
        std::cout << (ng ? "im" : "") << "possible\n";
    }
}