Prblm 42

#include <bits/stdc++.h>

using namespace std;
typedef long long int ll;
int main()
{
    ll n,i,j,count1=0,count2=0;
    cin>>n;
    char arr[n][n],min,max;
    
        for(i=0;i<n;i++)
        {
            for(j=0;j<n;j++)
            {
                cin>>arr[i][j];
            }
        }
        min=arr[0][0];
        max=arr[1][0];
        if(max==min)
        {
            cout<<"NO"<<endl;
            exit(0);
        }
        for(i=0;i<n;i++)
        {
  
            for(j=0;j<n;j++)
            {
                if(i==j)
                {
                    if(min==arr[i][i])
                    {
                        count1++;
                    }
                }
                else if(j==n-1-i)
                {
                    if(min==arr[i][j])
                    {
                        count1++;

                    }
                }
                else
                {
                    if(max==arr[i][j])
                    {
                       count2++;
                    }
                }

            }
        }

        if(count1==2*n-1&&count2==n*n-(2*n-1))
        {
            cout<<"YES"<<endl;
        }
        else
        {
            cout<<"NO"<<endl;
        }
    

    return 0;
}