# include "bits/stdc++.h"
using namespace std;
using LL = long long;
using ULL = unsigned long long;
const double PI = acos(-1);
template<class T>constexpr T INF() { return ::std::numeric_limits<T>::max(); }
template<class T>constexpr T HINF() { return INF<T>() / 2; }
template <typename T_char>T_char TL(T_char cX) { return tolower(cX); };
template <typename T_char>T_char TU(T_char cX) { return toupper(cX); };
const int vy[] = { -1, -1, -1, 0, 1, 1, 1, 0 }, vx[] = { -1, 0, 1, 1, 1, 0, -1, -1 };
const int dx[4] = { -1,0,1,0 }, dy[4] = { 0,-1,0,1 };
const char dir[4] = { 'u','l','d','r' };
int popcnt(unsigned long long n) { int cnt = 0; for (int i = 0; i < 64; i++)if ((n >> i) & 1)cnt++; return cnt; }
int d_sum(LL n) { int ret = 0; while (n > 0) { ret += n % 10; n /= 10; }return ret; }
int d_cnt(LL n) { int ret = 0; while (n > 0) { ret++; n /= 10; }return ret; }
LL gcd(LL a, LL b) { if (b == 0)return a; return gcd(b, a%b); };
LL lcm(LL a, LL b) { LL g = gcd(a, b); return a / g*b; };
# define ALL(qpqpq)           (qpqpq).begin(),(qpqpq).end()
# define UNIQUE(wpwpw)        (wpwpw).erase(unique(ALL((wpwpw))),(wpwpw).end())
# define LOWER(epepe)         transform(ALL((epepe)),(epepe).begin(),TL<char>)
# define UPPER(rprpr)         transform(ALL((rprpr)),(rprpr).begin(),TU<char>)
# define FOR(i,tptpt,ypypy)   for(LL i=(tptpt);i<(ypypy);i++)
# define REP(i,upupu)         FOR(i,0,upupu)
# define INIT                 std::ios::sync_with_stdio(false);std::cin.tie(0)
# pragma warning(disable:4996)


int t;
string s;
void solve() {
	int wcnt = 0, gcnt = 0, rcnt = 0;
	REP(i, s.size()) {
		if (s[i] == 'W')wcnt++;
		if (s[i] == 'G') {
			if (wcnt) {
				wcnt--;
				gcnt++;
			}
			else {
				cout << "impossible" << endl;
				return;
			}
		}
		if (s[i] == 'R') {
			if (gcnt) {
				gcnt--;
				rcnt++;
			}
			else {
				cout << "impossible" << endl;
				return;
			}
		}
	}
	if (gcnt) {
		cout << "impossible" << endl;
		return;
	}
	for (int i = s.size() - 1; i >= 0; i--) {
		if (s[i] == 'R')break;
		else {
			cout << "impossible" << endl;
			return;
		}
	}
	for (int i = s.size() - 1; i >= 0; i--) {
		if (s[i] != 'R') {
			if (s[i] == 'W') {
				cout << "impossible" << endl;
				return;
			}
			else {
				break;
			}
		}
	}
	cout << "possible" << endl;
	return;
}

int main() {
	cin >> t;
	REP(qqq, t) {
		cin >> s;
		solve();
	}
}