#include <bits/stdc++.h>
using namespace std;

int minimumSweatingFactor(vector<vector<int>> &a)
{
    int n = a.size();
    priority_queue<pair<int, pair<int, int>>, vector<pair<int, pair<int, int>>>, greater<pair<int, pair<int, int>>>> pq;
    pq.push({a[0][0], {0, 0}});
    vector<vector<bool>> visited(n, vector<bool>(n, false));
    int res = 0;
    while (!pq.empty())
    {
        auto temp = pq.top();
        pq.pop();
        int h = temp.first;
        int i = temp.second.first;
        int j = temp.second.second;
        visited[i][j] = true;
        res = max(res, h);
        if (i == n - 1 && j == n - 1)
        {
            return res;
        }

        if (i + 1 < n && !visited[i + 1][j])
        {
            pq.push({a[i + 1][j], {i + 1, j}});
        }
        if (j + 1 < n && !visited[i][j + 1])
        {
            pq.push({a[i][j + 1], {i, j + 1}});
        }
        if (i - 1 >= 0 && !visited[i - 1][j])
        {
            pq.push({a[i - 1][j], {i - 1, j}});
        }
        if (j - 1 >= 0 && !visited[i][j - 1])
        {
            pq.push({a[i][j - 1], {i, j - 1}});
        }
    }
    return 0;
}

signed main()
{
    int N;
    cin >> N;
    vector<vector<int>> grid(N, vector<int>(N));

    for (int i = 0; i < N; i++)
    {
        for (int j = 0; j < N; j++)
        {
            cin >> grid[i][j];
        }
    }

    cout << minimumSweatingFactor(grid) << endl;
}