#include <bits/stdc++.h>
#define INF 0x3f3f3f3f

using namespace std;

ifstream fin("alpin.in");
ofstream fout("alpin.out");

const int di[] = {-1, 0, 1, 0};
const int dj[] = {0, 1, 0, -1};

int n, v[1030][1030], matrDrum[1030][1030], is, js, maxim;

bool inMat(int i, int j) {
    return i >= 1 && i <= n && j >= 1 && j <= n;
}

inline int drum(int i, int j) {
    if(matrDrum[i][j] != 0) {
        return matrDrum[i][j];
    }
    int dist = 0;
    for(int d = 0; d < 4; d++) {
        int ii = i + di[d];
        int jj = j + dj[d];
        if(inMat(ii, jj) && v[ii][jj] > v[i][j]) {
            dist = max(dist, drum(ii, jj));
        }
    }
    matrDrum[i][j] = dist + 1;
    return matrDrum[i][j];
}

int main() {
    fin >> n;
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= n; j++) {
            fin >> v[i][j];
        }
    }
    fin.close();
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= n; j++) {
            int path = drum(i, j);
            if(path > maxim) {
                maxim = path;
                is = i, js = j;
            }
        }
    }
    fout << maxim;
    return 0;
}