#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <list>
#include <set>
#include <map>
#include <numeric>
#include <regex>
#include <tuple>
#include<iomanip>
using namespace std;

typedef long long ll;
typedef pair<int, int> P;
#define MOD 1000000007 // 10^9 + 7
#define INF 1000000000 // 10^9
#define LLINF 1LL<<60

string S[1000];

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	int N; cin >> N;
	for (int i = 0; i < N; i++) cin >> S[i];
	for (int i = 0; i < N; i++) {
		int W, G, R;
		W = G = R = 0;
		bool p = false;
		bool flag = true;

		for (int j = S[i].size() - 1; j >= 0 && flag; j--) {
			if (S[i][j] == 'W') {
				W++;
				if (R > 0 && G > 0) {
					W--; G--; R--;
					p = true;
				}
				else if (!p) flag = false;
			}
			if (S[i][j] == 'G') {
				G++;
			}
			if (S[i][j] == 'R') {
				R++;
			}

			if (G > R) flag = false;
		}
		if (G > 0 || R > 0) flag = false;

		if (flag) cout << "possible" << endl;
		else cout << "impossible" << endl;
	}

	return 0;
}