#include <stdio.h>

using namespace std;

int map[501][501];
int dp[501][501];
int ans=1;
int n;
int dy[] = { -1, 1 , 0 ,0 };
int dx[] = { 0,0,1,-1 };


int dfs(int y, int x ) {
    for (int i = 0; i < 4; i++) {
        int ny, nx;
        ny = y + dy[i];
        nx = x + dx[i];

        if (ny < 0 || nx < 0 || ny >= n || nx >= n || map[ny][nx] <= map[y][x]) continue;

        if (dp[ny][nx] > 1) {
            if (dp[y][x] < dp[ny][nx] + 1) {
                dp[y][x] = dp[ny][nx] + 1;
            }
        }
        else {
            int cnt = dfs(ny, nx);
            if (cnt > dp[y][x]) {
                dp[y][x] = cnt;
            }
        }
    }
    return dp[y][x] + 1;

}

int main() {

    int k;

    scanf_s("%d", &n);
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            scanf_s("%d",&map[i][j]);
            dp[i][j] = 1;
        }
    }

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            if (dp[i][j] == 1 ) {
                k = dfs(i, j) -1;
                if (k > ans) {
                    ans = k;
                }
            }

        }
    }

    printf_s("%d", ans);

    return 0;
}