package no154;

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.InputMismatchException;
import java.util.NoSuchElementException;

public class Main {

	public static void main(String[] args) {
		IO io = new IO();
		int t = io.nextInt();
		for(int tt=0;tt<t;tt++) {
			String s = io.next();
			io.println(isValid(s) ? "possible" : "impossible");
		}
		io.flush();
	}

	public static boolean isValid(String s) {
		//明らかにおかしい場合を弾く
		int w = 0;
		int g = 0;
		int r = 0;
		int n = s.length();
		for(int i=0;i<n;i++) {
			if (s.charAt(i) == 'R') {
				r++;
			}else if(s.charAt(i) == 'G') {
				g++;
			}else{
				w++;
			}
		}
		if (r != g || w < r || g == 0 && w > 0) {
			return false;
		}

		//最も右のGに注目する。その右側にはRしかないはず。GとRを1つずつ取る。そのGの左側から、次のG(もしくは先頭)までのWを取るか、Wがない場合Wを1つ取る。
		//これを繰り返す。

		String[] t = (s+"$").split("G"); //末尾にGがある場合を対策
//		System.out.println(Arrays.toString(t));
		int m = t.length;
		int[] wnum = new int[m];
		int[] rnum = new int[m];
		for(int i=0;i<m;i++) {
			for(int j=0;j<t[i].length();j++) {
				if (t[i].charAt(j) == 'W') {
					wnum[i]++;
				}else if(t[i].charAt(j) == 'R') {
					rnum[i]++;
				}
			}
		}
		int rsum = 0;
		int wr = m-1;
		for(int i=m-1;i>=1;i--) {
			if (wnum[i] > 0) {
				return false;
			}
			rsum += rnum[i];
			if (rsum <= 0) {
				return false;
			}
			rsum--;
			wr = Math.min(wr,i-2);
			if (wnum[i-1] > 0) {
				wnum[i-1] = 0;
			}else{
				boolean flag = false;
				for(;wr>=0;wr--) {
					if (wnum[wr] > 0) {
						flag = true;
						wnum[wr]--;
						break;
					}
				}
				if (!flag) {
					return false;
				}
			}
		}
		return true;
	}
}
class IO extends PrintWriter {
	private final InputStream in;
	private final byte[] buffer = new byte[1024];
	private int ptr = 0;
	private int buflen = 0;

	public IO() { this(System.in);}
	public IO(InputStream source) { super(System.out); this.in = source;}
	private boolean hasNextByte() {
		if (ptr < buflen) {
			return true;
		}else{
			ptr = 0;
			try {
				buflen = in.read(buffer);
			} catch (IOException e) {
				e.printStackTrace();
			}
			if (buflen <= 0) {
				return false;
			}
		}
		return true;
	}
	private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
	private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
	private static boolean isNewLine(int c) { return c == '\n' || c == '\r';}
	private void skipUnprintable() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;}
	private void skipNewLine() { while(hasNextByte() && isNewLine(buffer[ptr])) ptr++;}
	public boolean hasNext() { skipUnprintable(); return hasNextByte();}
	public boolean hasNextLine() { skipNewLine(); return hasNextByte();}
	public String next() {
		if (!hasNext()) {
			throw new NoSuchElementException();
		}
		StringBuilder sb = new StringBuilder();
		int b = readByte();
		while(isPrintableChar(b)) {
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	public char[] nextCharArray(int len) {
		if (!hasNext()) {
			throw new NoSuchElementException();
		}
		char[] s = new char[len];
		int i = 0;
		int b = readByte();
		while(isPrintableChar(b)) {
			if (i == len) {
				throw new InputMismatchException();
			}
			s[i++] = (char) b;
			b = readByte();
		}
		return s;
	}
	public String nextLine() {
		if (!hasNextLine()) {
			throw new NoSuchElementException();
		}
		StringBuilder sb = new StringBuilder();
		int b = readByte();
		while(!isNewLine(b)) {
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	public long nextLong() {
		if (!hasNext()) {
			throw new NoSuchElementException();
		}
		long n = 0;
		boolean minus = false;
		int b = readByte();
		if (b == '-') {
			minus = true;
			b = readByte();
		}
		if (b < '0' || '9' < b) {
			throw new NumberFormatException();
		}
		while(true){
			if ('0' <= b && b <= '9') {
				n *= 10;
				n += b - '0';
			}else if(b == -1 || !isPrintableChar(b)){
				return minus ? -n : n;
			}else{
				throw new NumberFormatException();
			}
			b = readByte();
		}
	}
	public int nextInt() {
		long nl = nextLong();
		if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) {
			throw new NumberFormatException();
		}
		return (int) nl;
	}
	public char nextChar() {
		if (!hasNext()) {
			throw new NoSuchElementException();
		}
		return (char) readByte();
	}
	public double nextDouble() { return Double.parseDouble(next());}
	public int[] arrayInt(int n) { int[] a = new int[n]; for(int i=0;i<n;i++) a[i] = nextInt(); return a;}
	public long[] arrayLong(int n) { long[] a = new long[n]; for(int i=0;i<n;i++) a[i] = nextLong(); return a;}
	public double[] arrayDouble(int n) { double[] a = new double[n]; for(int i=0;i<n;i++) a[i] = nextDouble(); return a;}
	public void arrayInt(int[]... a) {for(int i=0;i<a[0].length;i++) for(int j=0;j<a.length;j++) a[j][i] = nextInt();}
	public int[][] matrixInt(int n,int m) { int[][] a = new int[n][]; for(int i=0;i<n;i++) a[i] = arrayInt(m); return a;}
	public char[][] charMap(int n,int m) { char[][] a = new char[n][]; for(int i=0;i<n;i++) a[i] = nextCharArray(m); return a;}
	public void close() {
		super.close();
		try {
			in.close();
		} catch (IOException e) {}
	}
}