#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cstring>
#include <algorithm>
#include <limits.h>
#include <cmath>
#include <time.h>
#define REP(i,a,b) for(i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

int test = 0;
/* ここからが本編 */
int main(void)
{
  int i,j,k,l;
  int T;
  char S[1005] = "";

  cin >> T;
  while(cin >> S) {
    int n = strlen(S);
    int cnt = 0;
    bool possible = true;
    rep(i,n) {
      if(S[i] == 'G') cnt++;
      else if(S[i] == 'R') cnt--;
      if(cnt < 0) {
        possible = false;
        break;
      }
    }
    /* for(i=n-1;i>-1;i--) {

    }*/
    if(cnt != 0) possible = false;
    if(possible) puts("possible");
    else puts("impossible");
  }
  return 0;
}