#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define FOR(i,n,m) for(int i=(n);i<(m);i++)
#define REP(i,n) FOR(i,0,n)
#define REPR(i,n) for(int i=(n);i>=0;i--)
#define all(vec) vec.begin(),vec.end()
using vi=vector<int>;
using vvi=vector<vi>;
using vl=vector<ll>;
using vvl=vector<vl>;
using P=pair<int,int>;
using PP=pair<int,P>;
using Pl=pair<ll,ll>;
using PPl=pair<ll,Pl>;
using vs=vector<string>;
#define fi first
#define se second
#define pb push_back
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<class T>bool chmin(T &a,const T &b){if(a>b){a=b;return true;}return false;}
const ll MOD=1000000007LL;
const int INF=1<<30;
const ll LINF=1LL<<60;
void solve(string st){
    int r=0,g=0,w=0;
    REPR(i,st.size()-1){
        if(st[i]=='R'){
            r++;
        }else if(st[i]=='G'){
            if(r>0){
                g++;
                r--;
            }else{
                cout<<"impossible"<<endl;
                return;
            }
        }else{
            if(g>0){
                w++;
                g--;
            }else if(w==0){
                cout<<"impossible"<<endl;
                return;
            }
        }
    }
    cout<<"possible"<<endl;
    return;
}
int main(){
    int Q;
    cin>>Q;
    REP(i,Q){
        string st;
        cin>>st;
        solve(st);
    }
    return 0;
}