#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 cntW, cntG, cntR;
		cntW = cntG = cntR = 0;
		bool flag = true;

		for (int j = S[i].size()-1; j >=0 && flag; j--) {
			if (S[i][j] == 'W') {
				cntG--;
			}
			if (S[i][j] == 'G') {
				cntR--;
				cntG++;
			}
			if (S[i][j] == 'R') cntR++;
			if (cntR < 0 || cntG < 0) flag = false;
		}
		if (cntR > 0 && cntG > 0) flag = false;

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

	return 0;
}