#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <climits>
#include <cmath>
#include <string>
#include <vector>
#include <algorithm>
#include <queue>
#include <map>
#include <functional>
#include <set>
#include <numeric>
#include <stack>
#include <utility>
#include <time.h>
#include <iterator>
//#include "util.h"

using namespace std;
typedef unsigned uint;
typedef long long lint;
typedef unsigned long long ulint;



//呪文
template <typename _KTy, typename _Ty> ostream& operator << (ostream& ostr, const pair<_KTy, _Ty>& m) { cout << "{" << m.first << ", " << m.second << "}"; return ostr; }
template <typename _KTy, typename _Ty> ostream& operator << (ostream& ostr, const map<_KTy, _Ty>& m) { if (m.empty()) { cout << "{ }"; return ostr; } cout << "{" << *m.begin(); for (auto itr = ++m.begin(); itr != m.end(); itr++) { cout << ", " << *itr; } cout << "}"; return ostr; }
template <typename _Ty> ostream& operator << (ostream& ostr, const vector<_Ty>& v) { if (v.empty()) { cout << "{ }"; return ostr; }	cout << "{" << v.front(); for (auto itr = ++v.begin(); itr != v.end(); itr++) { cout << ", " << *itr; }	cout << "}"; return ostr; }
template <typename _Ty> ostream& operator << (ostream& ostr, const set<_Ty>& s) { if (s.empty()) { cout << "{ }"; return ostr; } cout << "{" << *(s.begin()); for (auto itr = ++s.begin(); itr != s.end(); itr++) { cout << ", " << *itr; }	cout << "}"; return ostr; }
//template <typename T> void print(T* v, int N) { if (N == 0) cout << "{ }"; cout << "{" << v[0]; for (int i = 1; i < N; i++) cout << ", " << v[i]; cout << "}"; }
#define PI 3.14159265358979323846
#define EPS 1e-8
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define all(x) (x).begin(), (x).end()



bool is_possible(string S)
{
	if (S.size() < 3) return false;

	map<char, int> f, b;
	for (int i = S.size() - 1; i >= 0; i--) {
		b[S[i]]++;
		if (b['R'] < b['G'] || b['G'] < b['W'] || b['R'] < b['W']) return false;
		if (b['W']) break;
	}
	for (int i = 0; i < S.size(); i++) {
		f[S[i]]++;
		if (f['W'] < f['G'] || f['G'] < f['R'] || f['W'] < f['R']) return false;
	}

	return f['G'] == f['R'];
}

int yuki0154()
{
	int T;
	cin >> T;

	string S;
	REP(i, T) {
		cin >> S;
		cout << (is_possible(S) ? "possible" : "impossible") << endl;
	}

	return 0;
}

int main()
{
	//clock_t start, end;
	//start = clock();

	yuki0154();

	//end = clock();
	//printf("%d msec.\n", end - start);

	return 0;
}