#include "bits/stdc++.h"
using namespace std;
#define rep(i, n) for(int i = 0; i < (n); i++)
#define REP(i, s, n) for(int i = (s); i < (n); i++)
#define all(co) begin(co), end(co)
#define maxup(ans, x) (ans = (ans < x ? x : ans))
#define minup(ans, x) (ans = (ans > x ? x : ans))
using P = pair<int, int>;

signed main() {
	int x = 0;
	int n; cin >> n;
	rep(_, n) {
		string s; cin >> s;
		int w = 0, g = 0, r = 0;
		bool ok = true;
		bool wg = false;
		for (char c : s) {
			if (c == 'W') { w++; wg = true; }
			if (c == 'G') { g++; wg = false; }
			if (c == 'R') { r++;  }
			if (g > w || r > g) {
				ok == false;
				break;
			}
		}
		cout << (wg && ok && g == r ? "possible" : "impossible") << endl;
	}
	//cin >> n;
}