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

int main()
{
    int T; cin>>T;
    while (T--) {
        string s; cin>>s;
        reverse(begin(s), end(s));

        int cnt[128]={};
        bool res=true;
        for(auto& c: s) {
            ++cnt[c];
            if (c=='W' and cnt['G']==0)
                res=false;
            else if (c=='G' and cnt['R']<cnt['G'])
                res=false;
        }
        if (cnt['R']==0 or cnt['R']!=cnt['G'] or cnt['W']<cnt['R'])
            res=false;

        cout<<(res ? "possible" : "impossible")<<endl;
    }
}