#include <bits/stdc++.h>
#define rep(i,n) for(int i=(0);i<(n);i++)

using namespace std;

typedef long long ll;
typedef unsigned long long ull;

template<class T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }

bool solve(string s){
	int n = s.size();

	int w = 0, g = 0, r = 0;
	rep(i, n){
		if(s[i] == 'G') g++;
		if(s[i] == 'R') r++;
		if(s[i] == 'W') w++;
 		if(w < g || g < r) return false;
	}

	if(g != r) return false;

	int gg = 0;
	rep(i, n){
		if(s[i] == 'G') gg++;
		if(s[i] == 'W'){
			if(gg == g) return false;
		}
	}

	return true;
}


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

	int q;
	cin >> q;

	vector<string> s(q);
	rep(i, q) cin >> s[i];
	rep(i, q) cout << (solve(s[i]) ? "possible" : "impossible")<< endl;
}