#include<iostream>
using namespace std;

int i =0 , j =0  , n =0 ;
int arr[100][100] = {0};

void NhapMang()
{
    cin >> n;
    for (int i =0 ; i < n ; i++)
    {
        for (int j =0 ; j < n ; j++)
        {
            cin >> arr[i][j];
        }
    }
}

int SoNguyenTo(int n)
{
    int  temp =0;
    for (i =2 ; i < n ; i++)
    {
        if (n % i == 0)
        {
            temp++;
        }
    }
    if (temp !=0 || n == 1 || n ==0)
    {
        return 0;
    }
    else
    {
        return 1;
    }
}

int Nchan()
{
    int temp =0 ;
    for(int i =0 ; i < n ; i++)
    {
        if(SoNguyenTo(arr[i][i]) == 1)
        {
            temp ++;
        }
    }
    for(int i =0 ; i < n ; i++)
    {
        for (int j =0 ; j < n ; j++)
        {
            if(SoNguyenTo(arr[i][n-1-i]) == 1)
            {
                temp++;
            }
            break;
        }
    }
    return temp ;
}

int Nle()
{
    int temp =0 , temp1 =0;
    temp1 = (n-1)/2;
    for(int i =0 ; i < n ; i++)
    {
        if(SoNguyenTo(arr[i][i]) == 1 && arr[i][i] != arr[temp1][temp1] )
        {
            temp ++;
        }
    }
    for(int i =0 ; i < n ; i++)
    {
        for (int j =0 ; j < n ; j++)
        {
            if(SoNguyenTo(arr[i][n-1-i]) == 1)
            {
                temp++;
            }
            break;
        }
    }
    return temp ;
}


int main()
{
    NhapMang();
    if (n % 2 ==0)
    {
     cout << Nchan() << endl;
    }
    else
    {
        cout << Nle() << endl;
    }

    return 0;
}