#include <bits/stdc++.h>
using namespace std;

int main() {
	int t;
	cin >> t;
	vector<string> s(t);
	for (int i = 0;i < t;i++) {
		cin >> s[i];
	}
	for (int i = 0;i < t;i++) {
		int w=0,g = 0, r = 0;
		bool b = true;
		for (int j = 0;j < s[i].size();j++) {
			switch (s[i][j]) {
			case 'W':
				w++;
				break;
			case 'G':
				g++;
				break;
			case 'R':
				r++;
				break;
			}
			if (w < g||g<r||w<r) {
				b = false;
				break;
			}
		}
		if (g != r) {
			b = false;
		}
		if (g == 0 && w > 0) {
			b = false;
		}
		for (int j = 0;j < s[i].size();j++) {
			if (s[i][j] == 'W') {
				w--;
			}
			if (s[i][j] == 'G') {
				g--;
				if (g == 0&&w>0) {
					b = false;
					break;
				}
			}
			if (s[i][j] == 'R') {
				r--;
				if (r == 0 && w > 0) {
					b = false;
					break;
				}
			}
		}
		cout << (b ? "possible" : "impossible") << endl;
	}




	return 0;
}