#include "bits/stdc++.h"
using namespace std;
#define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i))
#define rep(i,j) FOR(i,0,j)
#define each(x,y) for(auto &(x):(y))
#define mp make_pair
#define mt make_tuple
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<#x<<": "<<(x)<<endl
#define smax(x,y) (x)=max((x),(y))
#define smin(x,y) (x)=min((x),(y))
#define MEM(x,y) memset((x),(y),sizeof (x))
#define sz(x) (int)(x).size()
#define pb push_back
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vll;

const string Y = "possible", N = "impossible";
string S;

string solve() {
    int w = 0, ww = 0, g = 0;

    each(c, S) {
        if (c == 'W')w++, ww++;
        if (c == 'G') {
            g++;
            ww = 0;
            if (!w--)return N;
        }
        if (c == 'R') {
            if (!g--)return N;
        }
    }

    if (g > 0 || ww > 0)return N;
    return Y;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int T;
    cin >> T;
    
    while (T--) {
        cin >> S;
        cout << solve() << endl;
    }
}