#include <cstdio>
#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <string>
#include <cstring>
#include <sstream>
#include <algorithm>
#include <functional>
#include <queue>
#include <stack>
#include <cmath>
#include <iomanip>
using namespace std;
inline int toInt(string s) { int v; istringstream sin(s); sin >> v; return v; }
template<class T> inline string toString(T x) { ostringstream sout; sout << x; return sout.str(); }
template<class T> inline T sqr(T x) { return x*x; }
typedef pair<int, int> P;
typedef long long ll;
typedef unsigned long long ull;

#define rep(i,n)  for(int (i) = 0;(i) < (n);(i)++)
#define clr(a) memset((a), 0 ,sizeof(a))
#define mclr(a) memset((a), -1 ,sizeof(a))
#define all(a)  (a).begin(),(a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define sz(a) (sizeof(a))
#define Fill(a,v) fill((int*)a,(int*)(a+(sz(a)/sz(*(a)))),v)
bool cheak(int x, int y, int xMax, int yMax){ return x >= 0 && y >= 0 && xMax > x && yMax > y; }
const int dx[4] = { -1, 0, 1, 0 }, dy[4] = { 0, 1, 0, -1 };
const int mod = 1000000007;
const int INF = 2147483647;


int main()
{
	int n;
	cin >> n;

	rep(q, n){
		string s;
		cin >> s;
		int l = s.size();

		int f = 1;
		int r = 0,g = 0,w = 0;
		for (int i = l - 1; i >= 0; i--){
			if (s[i] == 'R'){
				r++;
			}else
			if (s[i] == 'G'){
				if (r < ++g)f = 0;
			}
			else{
				if (!g)f = 0;
				w++;
			}
		}
		if (r != g)f = 0;
		if (r > w)f = 0;

		if (f)cout << "possible" << endl;
		else  cout << "impossible" << endl;
	}

	return 0;
}