#include <bits/stdc++.h>

using namespace std;

#define rep(i, n) for(int i = 0; i < (int)n; ++i)
#define FOR(i, a, b) for(int i = a; i < (int)b; ++i)
#define rrep(i, n) for(int i = ((int)n - 1); i >= 0; --i)

typedef long long ll;
typedef long double ld;

const int Inf = 1e9;
const double EPS = 1e-9;
const int MOD = 1e9 + 7;

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(0);
    int t;
    cin >> t;
    rep (_, t) {
        string s;
        cin >> s;
        int cnt = 0;
        bool ok = true;
        rep (i, s.size()) {
            if (s[i] == 'G') cnt++;
            if (s[i] == 'R') cnt--;
            if (cnt < 0) ok = false;
        }
        if (cnt != 0) ok = false;
        if (ok) cout << "possible" << endl;
        else cout << "impossible" << endl;
    }
    
    return 0;
}