#include <bits/stdc++.h>
using namespace std;
struct INIT{INIT(){ios::sync_with_stdio(false);cin.tie(0);}}init;
bool check(string S){
    int white_count(0),green_count(0),white_exist(0);
    for(auto& it : S)
        switch(it){
            case 'W':white_count++;white_exist=1;break;
            case 'G':green_count++;white_exist=0;
                     if(white_count--<=0)return false;break;
            case 'R':if(green_count--<=0)return false;break;
        }
    return green_count==0&&white_exist==0;

}
int main() {
    int T;
    cin>>T;
    while(T--){
        string S;
        cin>>S;
        if(check(S))cout<<"possible"<<endl;
        else cout<<"impossible"<<endl;
    }
    return 0;
}