#include <bits/stdc++.h>
#define REP(i, n) for (int i = 0; i < (int)(n); i++)
#define REPR(i, n) for(int i = (int)(n); i >= 0; i--)
#define FOR(i, s, n) for (int i = (s); i < (int)(n); i++)
#define ALL(v) v.begin(), v.end()
using namespace std;
typedef long long ll;

ll N, T, K, W, H, M, C, V;

const int MAX = 510000;
const int MOD = 1e9;

const double PI=3.14159265358979323846;

long long fac[MAX], finv[MAX], inv[MAX];

vector<double> cx, cy, c;
 ll MM = 1e12;

void COMinit() {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (int i = 2; i < MAX; i++){
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }
}

long long COM(int n, int k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}

std::vector<int> Eratosthenes(int n ){
    std::vector<bool> is_prime( n + 1 );
    for( int i = 0; i <= n; i++ ) is_prime[ i ] = true;
    std::vector<int> P;
    for( int i = 2; i <= n; i++ ){
        if( is_prime[ i ] ){
            for( int j = 2 * i; j <= n; j += i ){
                is_prime[ j ] = false;
            }
            P.emplace_back( i );
        }
    }
    return P;
}

int main(){
    cin >> N ;
    REP(i,N){
        string str;
        cin >> str;
        int num = 0;
        int r = 0;
        int g = 0;
        int w = 0;
        bool flag = true;
        for(int i = str.size()-1; i >= 0; --i){
            if( (r <= 0 or g <= 0) and str[i] == 'W'){
                flag = false;
            }
            if(str[i] == 'W') ++w;
            if(str[i] == 'R') {++num; ++r;}
            if(str[i] == 'G'){
                ++g;
                if(num > 0) --num;
            }
        }
        if(!num and g==r and flag and w >= g) cout << "possible";
        else cout << "impossible";
        cout << "\n";
    }
    return 0;
}