#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <sstream>
#include <cstring>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <numeric>
#include <cctype>
#include <tuple>
#include <array>
#include <climits>
#include <bitset>
#include <cassert>

#ifdef _MSC_VER
#include <agents.h>
#endif

#define FOR(i, a, b) for(int i = (a); i < (int)(b); ++i)
#define rep(i, n) FOR(i, 0, n)
#define ALL(v) v.begin(), v.end()
#define REV(v) v.rbegin(), v.rend()
#define MEMSET(v, s) memset(v, s, sizeof(v))
#define UNIQUE(v) (v).erase(unique(ALL(v)), (v).end())
#define MP make_pair
#define MT make_tuple

using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<int, int> P;

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout.setf(ios::fixed);
	cout.precision(20);

	int t;
	cin >> t;
	while (t--){
		string s;
		cin >> s;
		reverse(ALL(s));
		int cnt[2] = {};
		int n = s.size();
		bool b = true, g = false;
		rep(i, n){
			if (s[i] == 'R') ++cnt[0];
			if (s[i] == 'G'){
				g = true;
				if (!cnt[0]) b = false;
				--cnt[0];
				++cnt[1];
			}
			if (s[i] == 'W'){
				if (!g) b = false;
				if (cnt[1]) --cnt[1];
			}
		}
		if (cnt[0] + cnt[1]) b = false;
		cout << ("impossible" + b*2) << endl;
	}

}