#include "bits/stdc++.h"
#define REP(i,n,N) for(ll i=(n); i<(N); i++)
#define RREP(i,n,N) for(ll i=(N-1); i>=n; i--)
#define CK(n,a,b) ((a)<=(n)&&(n)<(b))
#define ALL(v) (v).begin(),(v).end()
#define p(s) cout<<(s)<<endl
#define p2(a,b) cout<<(a)<<" "<<(b)<<endl
#define v2(T) vector<vector<T>>
typedef long long ll;
using namespace std;
const int INF = 1e9;
const int MOD = 1e9+7;
const ll LLINF = 1e18;

int main(){
    int T;
    string s;
    cin>>T;
    while(T--){
        bool ok=true;
        cin>>s;
        int cnt=0;
        RREP(i,0,s.size()){
            if(s[i]=='R'){
                cnt++;
            }else if(s[i]=='G'){
                cnt--;
            }
            if(cnt<0) {
                ok = false;
            }
        }
        RREP(i,0,s.size()){
            if(s[i]=='W'){
               ok=false;
            }else if(s[i]=='G'){
                break;
            }
        }
        p(ok?"possible":"impossible");
    }

    return 0;
}