#include<bits/stdc++.h>

using namespace std;
using ll = long long;

int main(){
    int t;
    string s;
    cin >> t;
    while(t--){
        cin >> s;
        bool ok = false;
        int g = 0,r = 0;
        if(s[s.size()-1] != 'R'){
            cout << "impossible" << endl;
        }else{
            for(int i=s.size()-1;i >= 0;i--){
                if(s[i] == 'W'){
                    if(g > 0 && r > 0){
                        ok = true;
                        g--;r--;
                    }
                }else if(s[i] == 'G'){
                    if(r > 0) g++;
                }else if(s[i] == 'R'){
                    r++;
                }
            }
            cout << (ok ? "possible" : "impossible") << endl;
        }
}
    return 0;
}