#include <iostream>
#include <cstdio>
#include <string>
#include <vector>
#include <cmath>
#include <algorithm>

using namespace std;

#define REP(i,n)	for(int i=0;i<(n);++i)
#define REPS(i,s,t)	for(int i=(s);i<(t);++i)
#define PER(i,n)	for(int i=0;i>(n);--i)
#define PERS(i,s,t)	for(int i=(s);i>(t);--i)

#define INF 		2000000007
#define MINF		-200000007
#define MOD			17 	
// 2^20

#define MAX 		100005

typedef unsigned int 			uint;
typedef unsigned long long int	ull;
typedef long long int 			ll;

//int dp[4912];

int main(){
	int N;cin>>N;

	REP(i,N){
		string str;cin>>str;
		bool flag = true;
		int cntw=0,cntr=0,cntg=0;
		PERS(j,str.size()-1,-1){
			if(str[j]=='R'){cntr++;}
			else if(str[j]=='G'){cntg++;}
			else cntw++;
			if(cntr-cntg<0) {flag = false;break;}
			if((cntw&&!cntr) || (cntw&&!cntg)){flag=false;break;}
		}
		if(cntw < cntr || cntr-cntg!=0 || !cntr) flag = false;
		cout << (flag ? "possible\n" : "impossible\n") ;
	}


	return 0;
}