import java.math.*;
import java.util.*;

class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int t = sc.nextInt();
		ee:for(int i=0;i<t;i++){
			String string = sc.next();
			int gc=0;
			int rc=0;
			int wc=0;
			boolean flag=true;
			for(int j=0;j<string.length();j++){
				if(string.charAt(j)=='G') gc++;
				if(string.charAt(j)=='R') rc++;
				if(string.charAt(j)=='W') wc++;
				if(gc<rc){
					System.out.println("impossible");
					continue ee;
				}
				if(wc<gc){
					System.out.println("impossible");
					continue ee;
				}
			}
			if(gc==0||rc==0||wc==0){
				System.out.println("impossible");
				continue;
			}
			if(wc<gc){
				System.out.println("impossible");
				continue;
			}
			if(gc!=rc){
				System.out.println("impossible");
				continue;
			}
			if(string.lastIndexOf("R")<string.lastIndexOf("G")){
				System.out.println("impossible");
				continue;
			}
			if(string.lastIndexOf("G")<string.lastIndexOf("W")){
				System.out.println("impossible");
				continue;
			}
			if(string.indexOf("R")<string.indexOf("G")){
				System.out.println("impossible");
				continue;
			}
			
			System.out.println("possible");
			
		}
	}
}