// Author: btjanaka (Bryon Tjanaka)

// Problem: (UVa) 10102

#include <bits/stdc++.h>

using namespace std;

char field[200][200];

int main() {

int m;

while (scanf("%d", &m) > 0) {

// Input

for (int i = 0; i < m; ++i) {

scanf("%s", field[i]);

}

// Go through the entire grid looking for 1's (initial states); for each

// one, look for the nearest 3. The maximum of these distances is the

// minimum distance needed to get to a 3 from an initial state.

int max_min_d = -1;

for (int i = 0; i < m; ++i) {

for (int j = 0; j < m; ++j) {

if (field[i][j] == '1') {

bool found_three = false;

for (int x = 0; x < m && !found_three; ++x) {

for (int y = 0; y < m && !found_three; ++y) {

if ((i + x < m && j + y < m && field[i + x][j + y] == '3') ||

(i - x >= 0 && j - y >= 0 && field[i - x][j - y] == '3')) {

max_min_d = max(max_min_d, x + y);

found_three = true;

}

}

}

}

}

}

// Output

printf("%d\n", max_min_d);

}

return 0;

}