#include <iostream>
#include <string>

using namespace std;

auto T=0;

void input(){
    cin >> T;
}

void solve(){
    for(int i=0; i<T; i++){
        string s;
        cin >> s;
        if(s.size()<3){
            cout << "impossible" << endl;
            continue;
        }
        
        auto r_cnt = 0, g_cnt = 0, w_cnt = 0;
        bool ans = true, f = false;
        for(int j=0;j<s.size();j++){
            switch(s[j]){
                case 'R':
                    r_cnt++;
                    break;
                case 'G':
                    f=true;
                    g_cnt++;
                    break;
                case 'W':
                    w_cnt++;
                    f=false;
                    break;
            }

            if(!(w_cnt>=g_cnt&&g_cnt>=r_cnt)){
                ans = false;
                break;
            }
        }
        if(g_cnt!=r_cnt||!f) ans = false;

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

int main(){
    input();
    solve();
}