#include<algorithm>
#include<complex>
#include<ctype.h>
#include<iomanip>
#include<iostream>
#include<fstream>
#include<map>
#include<math.h>
#include<numeric>
#include<queue>
#include<set>
#include<stack>
#include<stdio.h>
#include<string>
#include<string>
#include<vector>

using namespace std;
typedef long long ll;

#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout<<(s)<<endl
#define p2(s, t) cout << (s) << " " << (t) << endl
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << endl
#define p_yes() p("Yes")
#define p_no() p("No")

const ll mod = 1e9 + 7;
const ll inf = 1e18;

template < typename T >
void vprint(T &V){
	for(auto v : V){
    	cout << v << " ";
	}
	cout << endl;
}

bool is_correct(string s){
    reverse(ALL(s));
    ll r = 0;
    ll g = 0;
    ll w = 0;

    for(char c : s){
        if(c=='R'){
            r++;
        }
        else if(c=='G'){
            g++;
            if(g>r) return false;
        }
        else{
            w++;
            if(r==0 || g==0) return false;
            if(r!=g && min(r, g)<w) return false;
        }
    }
    if(r==0 || g==0) return false;

    if(r!=g) return false;

    if(w<r) return false;

    return true;
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    // input
    ll N;
    cin >> N;

    FOR(i, 0, N){
        string s;
        cin >> s;
        if(is_correct(s)){
            p("possible");
        }else{
            p("impossible");
        }
    }
    
    return 0;
}