#include <iostream>
using namespace std;
int cantVisit = 100;
void countMin(int board[][10], int KnightCanVisit[][10], int n){
int count = 0;
for (int i = 0; i < n; i++){
for (int j = 0; j < n; j++){
if (KnightCanVisit[i][j] == 1){
count++;
}
}
}
cantVisit = min(cantVisit, count);
}
void knightMoves(int board[][10], int KnightCanVisit[][10], int i, int j, int n){
if (i > n || j > n || i < 0 || j < 0){
return;
}
if (board[i][j] == 0 || KnightCanVisit[i][j] == 1){
return;
}
KnightCanVisit[i][j] = 1;
countMin(board, KnightCanVisit, n);
knightMoves(board, KnightCanVisit, i + 2, j + 1, n);
knightMoves(board, KnightCanVisit, i + 2, j - 1, n);
knightMoves(board, KnightCanVisit, i - 2, j + 1, n);
knightMoves(board, KnightCanVisit, i - 2, j - 1, n);
knightMoves(board, KnightCanVisit, i - 1, j + 2, n);
knightMoves(board, KnightCanVisit, i + 1, j + 2, n);
knightMoves(board, KnightCanVisit, i - 1, j - 2, n);
knightMoves(board, KnightCanVisit, i + 1, j - 2, n);
KnightCanVisit[i][j] = 0;
}
int main(){
int n;
cin >> n;
int board[10][10];
int KnightCanVisit[10][10] = {0};
for (int i = 0; i < n; i++){
for (int j = 0; j < n; j++){
cin >> board[i][j];
}
}
knightMoves(board, KnightCanVisit, 0, 0, n);
cout << cantVisit << endl;
return 0;
}
