#include<iostream>
#include<cstring>
using namespace std;

int main()
{
	int t, wcount = 0, gcount = 0, rcount = 0;
	char s[1001];

	cin >> t;

	int miss = 0;
	for (int i = 1; i <= t; i++)
	{
		cin >> s;

		for (int j = strlen(s); j >= 0; j--)
		{
			if (s[j] == 'R')
			{
				rcount++;
			}
			if (s[j] == 'G')
			{
				if (rcount > 0)
				{
					gcount++;
					rcount--;
				}
				else
				{
					miss++;
				}
			}
			if (s[j] == 'W')
			{
				if (gcount > 0)
				{
					gcount--;
					wcount++;
				}
				else if (wcount > 0)
				{
					wcount++;
				}
				else
				{
					miss++;
				}
			}
		}

		if ((rcount != 0 || gcount != 0) || miss > 0)
		{
			cout << "impossible" << endl;
		}
		else
		{
			cout << "possible" << endl;
		}
		miss = 0;
		wcount = 0;
		gcount = 0;
		rcount = 0;
	}
}