#include <iostream>
#include <math.h>
#include <vector>
#include <array>
#include <algorithm>
#include <queue>
#include <numeric>
#include <map>
#include <set>

using namespace std;
#define int long long
#define FOR(i, a, b) for(int i=(a);i<(b);i++)
#define RFOR(i, a, b) for(int i=(b-1);i>=(a);i--)
#define REP(i, n) for(int i=0; i<(n); i++)
#define RREP(i, n) for(int i=(n-1); i>=0; i--)
#define ALL(a) (a).begin(),(a).end()
#define UNIQUE_SORT(l) sort(ALL(l)); l.erase(unique(ALL(l)), l.end());
#define CONTAIN(a, b) find(ALL(a), (b)) != (a).end()
#define array2(type, x, y) array<array<type, y>, x>
#define vector2(type) vector<vector<type> >
#define out(...) printf(__VA_ARGS__)

typedef pair<int, int> pos;
int pos::*x = &pos::first;
int pos::*y = &pos::second;

int dxy[] = {0, 1, 0, -1, 0};

/*================================*/

int T;
vector<bool> r;

signed main()
{
    cin >> T;
    map<char, int> c;
    string s;
    REP(i,T) {
        cin >> s;
        c['R'] = c['G'] = c['W'] = 0;
        bool ret = true;
        int newr = 0;
        int newg = 0;
        RREP(j,s.size()) {
            c[s[j]]++;
            if (s[j] == 'R') newr++;
            if (s[j] == 'G') {
                newg++;
                if (c['G'] > c['R']) ret = false;
            }
            if (s[j] == 'W') {
                if (newr > 0 && newg > 0) {
                    newr = max((int)0, newr - 1);
                    newg = max((int)0, newg - 1);
                }
                if (c['R'] == 0 || c['G'] == 0) ret = false;
            }
        }
        if (newr > 0 || newg > 0) ret = false;
        if (c['G'] != c['R']) ret = false;
        if (c['W'] < c['R']) ret = false;
        r.push_back(ret);
    }
    
    REP(i,T) cout << (r[i] ? "possible" : "impossible") << endl;
    
    return 0;
}