#include <iostream>
using namespace std;

int main(){
	int t;
	cin >> t;
	while(t--){
		string s;
		cin >> s;
		string tmp = s;
		for(int i = 0;i < tmp.size();i++) if(tmp[i] != 'W') tmp.erase(tmp.begin() + i);
		if(tmp.size() == s.size()){
			cout << "impossible" << endl;
			continue;
		}
		tmp = s;
		int w,g,r;
		for(int i = s.size();i--;){
			bool f = false;
			if(s[i] == 'R'){
				r = i;
				for(int j = i;--j > 0;){
					if(s[j] == 'G'){
						g = j;
						for(int k = j;--k >= 0;){
							if(s[k] == 'W'){
								w = k;
								f = true;
								j = k = 0;
							}
						}
					}
				}
			}
			if(f){
				for(int j = r;++j < s.size();) if(s[j] != 'R') f = false;
				for(int j = g;++j < s.size();) if(s[j] == 'W') f = false;
			}
			if(f){
				s.erase(s.begin() + r);
				s.erase(s.begin() + g);
				s.erase(s.begin() + w);
			}
		}
		bool flag = true;
		for(int i = 0;i < s.size();i++) if(s[i] != 'W') flag = false;
		//cout << (flag ? "possible" : "impossible") << endl;
		s = tmp;
		for(int i = s.size();i--;){
			bool f = false;
			if(s[i] == 'R'){
				r = i;
				for(int j = i;--j > 0;){
					if(s[j] == 'G'){
						g = j;
						for(int k = j;--k >= 0;){
							if(s[k] == 'W'){
								w = k;
								f = true;
								j = k = 0;
							}
						}
					}
				}
			}
			if(f){
				s.erase(s.begin() + r);
				s.erase(s.begin() + g);
				s.erase(s.begin() + w);
			}
		}
		bool flag2 = true;
		for(int i = 0;i < s.size();i++) if(s[i] != 'W') flag2 = false;
		cout << (flag || flag2 ? "possible" : "impossible") << endl;
	}
}