#include <bits/stdc++.h>

using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()

template<typename A, typename B> inline bool chmax(A &a, B b) { if (a<b) { a=b; return 1; } return 0; }
template<typename A, typename B> inline bool chmin(A &a, B b) { if (a>b) { a=b; return 1; } return 0; }

typedef unsigned long long ull;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<int, pii> P;

const ll INF = 1ll<<60;
const ll MOD = 1000000007;
const double EPS  = 1e-10;

int main() {
	int t;
	cin >> t;
	
	REP(i, t) {
		string s;
		cin >> s;
		
		int w = 0, g = 0, r = 0;
		bool ng = false;
		
		REP(i, s.size()) {
			switch (s[i]) {
				case 'W': w++; break;
				case 'G': if (w == 0) ng = true; w--; g++; break;
				case 'R': if (g == 0) ng = true; g--; r++; break;
			}
		}
		
		if (w < 0 || g > 0) ng = true;
		
		w = g = r = 0;
		for (int i = s.size() - 1; i >= 0; i--) {
			switch (s[i]) {
				case 'W': if (g == 0) ng = true; w++; break;
				case 'G': if (r == 0) ng = true; r--; g++; break;
				case 'R': r++; break;
			}
		}
		
		puts(ng ? "impossible" : "possible");
	}
	return 0;
}