#include <cstdio>
#include <iostream>
#include <string>
#include <sstream>
#include <stack>
#include <algorithm>
#include <cmath>
#include <queue>
#include <map>
#include <set>
#include <cstdlib>
#include <bitset>
#include <tuple>
#include <assert.h>
#include <deque>
#include <bitset>
#include <iomanip>
#include <limits>
#include <chrono>
#include <random>
#include <array>
#include <unordered_map>
#include <functional>
#include <complex>

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

const long long MAX = 5100000;
const long long INF = 1LL << 60;
const long long mod = 1000000007LL;
//const long long mod = 998244353LL;

using namespace std;
typedef unsigned long long ull;
typedef long long ll;


int main()
{
	/*
	cin.tie(nullptr);
	ios::sync_with_stdio(false);
	*/
	ll N; scanf("%lld", &N);
	while (N--) {
		string s; cin >> s;
		ll cnt = 0;
		bool flag = true;
		for (ll i = 0; i < s.size(); i++) {
			if (s[i] == 'G') cnt++;
			else if (s[i] == 'R') {
				if (cnt == 0) {
					flag = false;
					break;
				}
				else {
					cnt--;
				}
			}
		}
		if (flag && cnt == 0) puts("possible");
		else puts("impossible");
	}
	return 0;
}