import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.PrintWriter; import java.util.Queue; import java.util.StringTokenizer; public class Main { void solve() throws IOException { int n = ni(); out: for (int i = 0; i < n; i++) { String s = ns(); if (s.length() < 3) { out.println("impossible"); continue; } int cntG = 0, cntR = 0, cntW = 0; for (int j = 0; j < s.length(); j++) { if (s.charAt(j) == 'G') { cntG++; cntW = 0; } else if (s.charAt(j) == 'R') { cntR++; } else { cntW++; } if (cntG < cntR) { out.println("impossible"); continue out; } } if (cntW == 0 && cntG == cntR) { out.println("possible"); } else { out.println("impossible"); } } } String ns() throws IOException { while (!tok.hasMoreTokens()) { tok = new StringTokenizer(in.readLine(), " "); } return tok.nextToken(); } int ni() throws IOException { return Integer.parseInt(ns()); } long nl() throws IOException { return Long.parseLong(ns()); } double nd() throws IOException { return Double.parseDouble(ns()); } String[] nsa(int n) throws IOException { String[] res = new String[n]; for (int i = 0; i < n; i++) { res[i] = ns(); } return res; } int[] nia(int n) throws IOException { int[] res = new int[n]; for (int i = 0; i < n; i++) { res[i] = ni(); } return res; } long[] nla(int n) throws IOException { long[] res = new long[n]; for (int i = 0; i < n; i++) { res[i] = nl(); } return res; } static BufferedReader in; static PrintWriter out; static StringTokenizer tok; public static void main(String[] args) throws IOException { in = new BufferedReader(new InputStreamReader(System.in)); out = new PrintWriter(System.out); tok = new StringTokenizer(""); Main main = new Main(); main.solve(); out.close(); } }