#include <bits/stdc++.h>
using namespace std;
#define all(c) (c).begin(),(c).end()
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;i--)
#define REP(i,m,n) for(int i=(int)(m);i<(int)(n);i++)
#define rep(i,n) REP(i,0,n)
#define iter(c) __typeof((c).begin())
#define tr(it,c) for(iter(c) it=(c).begin();it!=(c).end();it++)
#define pb(a) push_back(a)
#define pr(a) cout<<(a)<<endl
#define PR(a,b) cout<<(a)<<" "<<(b)<<endl
#define R cin>>
#define F first
#define S second
#define ll long long
bool check(int n,int m,int x,int y){return (x<0||x>=n||y<0||y>=m)?false:true;}
const ll MAX=1000000007,MAXL=1LL<<60,dx[4]={-1,0,1,0},dy[4]={0,1,0,-1};
typedef pair<int,int> P;

int main() {
  int T;
  cin >> T;
  while(T--) {
    string s;
    cin >> s;
    int k=0;
    bool ck=true,ck2=true;
    rrep(i,s.size()) {
      if(s[i]=='R') k++;
      if(s[i]=='G') {
	k--;
	ck2=false;
      }
      if(k<0 || (ck2 && s[i]=='W')) ck=false;
    }
    if(ck && !k) cout << "possible" << endl;
    else cout << "impossible" << endl;
  }
  return 0;
}