#include "bits/stdc++.h"
using namespace std;
#ifdef _DEBUG
#include "dump.hpp"
#else
#define dump(...)
#endif

//#define int long long
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(c) begin(c),end(c)
const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = 1'000'000'007;
template<class T> bool chmax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T &a, const T &b) { if (b < a) { a = b; return true; } return false; }

signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int N; cin >> N;
	rep(i, 0, N) {
		string s; cin >> s;
		bool ok = true;
		queue<int> w, g, r;
		rep(i, 0, s.size()) {
			if (s[i] == 'W')w.push(i);
			if (s[i] == 'G')g.push(i);
			if (s[i] == 'R')r.push(i);
		}
		while (w.size() && g.size() && r.size()) {
			int a = w.front(); w.pop();
			int b = g.front(); g.pop();
			int c = r.front(); r.pop();
			if (a < b && b < c) {
				continue;
			}
			ok = false;
		}
		if (g.size() || r.size())
			ok = false;

		cout << (ok ? "possible" : "impossible") << endl;
	}
	return 0;
}