#include <iostream>
#include <string>
using namespace std;

int main()
{
    int T; cin>>T;
    while (T--) {
        string s; cin>>s;
        int cnt[128]={};
        string res="possible";
        for(auto& c: s) {
            ++cnt[c];
            if (c=='R' and !(cnt['W']>=cnt['G'] and cnt['G']>=cnt['R']))
                res="impossible";
            if (c=='G' and !(cnt['W']>=cnt['G']))
                res="impossible";
        }
        if (cnt['G']!=cnt['R'] or cnt['G']==0)
            res="impossible";

        cout<<res<<endl;
    }
}