#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    int T; cin >> T;
    rep(_,T) {
        string S; cin >> S;
        int W = 0, G = 0, R = 0;
        int N = S.size();
        int ans = 1;
        for(int i = N - 1; i >= 0; i--) {
            if(S[i] == 'W') {
                ans &= G != 0;
                W = min(G, W + 1);
            }
            if(S[i] == 'G') {
                G++;
                ans &= G <= R;
            }
            if(S[i] == 'R') R++;
        }
        ans &= R <= G && G <= W;
        cout << string(ans ? "" : "im") + "possible" << endl;
    }
}