#include "bits/stdc++.h"
using namespace std;
#define print(x) cout<<x<<endl;
#define rep(i,a,b) for(int i=a;i<b;i++)
#define REP(i,a) for(int i=0;i<a;i++)
#define GET_ARRAY_SIZE(a) (sizeof(a)/sizeof(a[0]))
typedef long long ll;
typedef pair<int, int> PI;
typedef pair<int, PI> V;
typedef vector<int> VE;
const ll mod = 1000000007;

int main(){
  int n;
  cin>>n;
  REP(i,n){
    string s;
    cin>>s;
    int cnt=0;
    bool flag=1;
    REP(j,GET_ARRAY_SIZE(s)){
      if(s[j]=='G'){cnt++;}
      else if(s[j]=='R'){cnt--;}
      if(cnt<0)flag=0;
      //print(s[j]<<" "<<cnt);
    }
    string ans=cnt==0&&flag?"possible":"impossible";
    print(ans);
  }
}