#include <bits/stdc++.h>

using namespace std;

int T, N;
string S;

bool rec(int number = 0){
    
    if(number == N) return true;
    
    int r = 0, m = 0, n = 0;
    int flag = false;
    
    if((r = S.find("W")) != string::npos && r < S.size()){
        if((m = S.find("G", r)) != string::npos && m < S.size()){
            if((n = S.find("R", m)) != string::npos && n < S.size()){
                S.erase(S.begin() + r);
                S.erase(S.begin() + (m - 1));
                S.erase(S.begin() + (n - 2));
                flag = rec(number + 1);
            }
        }
    }
    
    return flag;
}

int main(void){
    
    cin >> T;
    
    int i, j, k, p;
    for(i = 0; i < T; ++i){
        cin >> S;
        
        j = k = p = 0;
        while((p = S.find("G", p)) != string::npos && p <= S.size()){
            ++j;
            ++p;
        }
        p = 0;
        while((p = S.find("R", p)) != string::npos && p <= S.size()){
            ++k;
            ++p;
        }
        
        if(j != k){
            cout << "impossible" << endl;
        }
        else{
            N = j;
            k = 0;
            for(j = S.size(); j >= 0; --j){
                if(S[j] == 'W') ++k;
                if(k == N) break;
            }
            S.erase(S.begin(), S.begin() + (j - 1));
            if(rec()){
                cout << "possible" << endl;
            }
            else cout << "impossible" << endl;
        }
        
    }
    
    return 0;
}