#include <bits/stdc++.h>
using namespace std;

//repetition
#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define rep(i, n) for(ll i = 0; i < (ll)(n); i++)

//container util
#define all(x) (x).begin(),(x).end()

//typedef
typedef long long ll;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<ll> VLL;
typedef vector<VLL> VVLL;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;

//const value
//const ll MOD = 1e9 + 7;
//const int dx[] = {0,1,0,-1};//{0,0,1,1,1,-1,-1,-1};
//const int dy[] = {1,0,-1,0};//{1,-1,0,1,-1,0,1,-1};

//conversion
inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
inline ll toLL(string s) {ll v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}


int main(){
  ios::sync_with_stdio(false);
  cin.tie(0);
  ll n;
  cin >> n;
  rep(i,n){
    string x;
    cin >> x;
    priority_queue<ll> gque;
    priority_queue<ll> rque;
    priority_queue<ll> wque;
    ll Wmax = -1;
    rep(j,x.size()){
      if(x[j] == 'G') gque.push(j);
      if(x[j] == 'R') rque.push(j);
      if(x[j] == 'W') wque.push(j);
    }
    if(x.size() < 3) {cout << "impossible" << "\n"; continue;}
    if(gque.size() != rque.size() || wque.size() < gque.size()) {cout << "impossible" << "\n"; continue;}
    bool impFlag = false;

    while(rque.empty() == false){
      ll rtop = rque.top(); rque.pop();
      ll gtop = gque.top(); gque.pop();
      ll wtop = wque.top(); wque.pop();
      if(rtop > gtop && gtop > wtop ) continue;
      else impFlag = true; break;
    }

    if(impFlag) cout << "impossible" << "\n";
    else cout << "possible" << endl;
  }
  return 0;
}