#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <numeric>
#include <functional>
#include <cmath>
#include <queue>
#include <stack>
#include <set>
#include <map>

#define repd(i,a,b) for (int i=(a);i<(b);i++)
#define rep(i,n) repd(i,0,n)
typedef long long ll;

using namespace std;


int inputValue(){
    int a;
    cin >> a;
    return a;
};

template <typename T>
void output(T a, int precision) {
    if(precision > 0){
        cout << setprecision(precision)  << a << "\n";
    }
    else{
        cout << a << "\n";
    }
}

int main() {
    
    // source code
    
    int N = inputValue();
    
    rep(i, N){
        string s;
        cin >> s;
        
        int check = 0;
        
        rep(j, s.size()){
            if (s[j] == 'G') {
                check++;
            }
            if (s[j] == 'R') {
                check--;
            }
            if (check < 0) {
                break;
            }
        }
        output((check == 0) ? "possible" : "impossible", 0);
    }
    
    return 0;
}