#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int>   II;
typedef vector<int>     VI;
typedef long long int   LL;
#define PB push_back
#define MP make_pair
#define F first
#define S second
#define SZ(a) (int)(a.size())
#define ALL(a) a.begin(),a.end()
#define SET(a,b) memset(a,b,sizeof(a))
bool ok;
bool check(vector<string> &G, string &A,int root)
{
    int n = SZ(G);
    vector<int> vis(n,0);
    vis[root]=1;
    queue<int> Q;Q.push(root);
    int done=0;
    while(!Q.empty())
    {
        int u = Q.front();Q.pop();done++;
        for(int i=0;i<n;i++)
            if(!vis[i] && G[u][i]==A[i])
            {
                vis[i]=1;
                Q.push(i);
            }
    }
    return done==n;
}
int idx(char c)
{
    if(c=='R')return 0;
    if(c=='G')return 1;
    if(c=='B')return 2;
    return -1;
}
void solve(int i,vector<string> &G,string &A)
{
    if(i==SZ(G))
    {
        int n = SZ(G);
        int cnt[]={0,0,0};
        for(int i=0;i<n;i++)
            cnt[idx(A[i])]++;
        int k = (n-1)/3;
        char c='.';
        for(int i=0;i<3;i++)
            if(cnt[i]==k+1)
                c = (i?(i==1?'G':'B'):'R');
        if(c=='.')return;
        for(int i=0;i<3;i++)
            if(i!=idx(c) && cnt[i]!=k)
                return;
        for(int i=0;i<n;i++)
            if(A[i]==c && check(G,A,i))
                ok=true;
        return;
    }
    solve(i+1,G,(A[i]='R',A));
    solve(i+1,G,(A[i]='G',A));
    solve(i+1,G,(A[i]='B',A));
}
class RGBTree {
public:
    string exist(vector <string> G) {
        ok=false;
        string A(SZ(G),'.');
        solve(0,G,A);
        return ok?"Exist":"Does not exist";
    }
};