import java.util.Scanner;

public class Rec {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();
        int[][] rec = new int[n][n];
        for(int i = 0 ; i < n ; ++i) {
            for(int  j = 0 ; j < n ; ++i) {
                rec[i][j] = scan.nextInt();
            }
        }
        for(int i = 1 ; i < n ; ++i) {
            for(int j = 0 ; j < n ; ++j) {
                int mx = -1;
                for(int k = 0 ; k < n ; ++k) {
                    if(k != j) {
                        mx = Math.max(mx, rec[i-1][k] + rec[i][j]);
                    }
                }
                rec[i][j] = mx;
            }
        }
        System.out.println(findMax(rec));
    }

    private static int findMax(int[][] rec) {
        int mx = rec[rec.length - 1][0];
        for(int i = 0 ; i < rec.length ; ++i) {
            mx = Math.max(mx, rec[rec.length - 1][i]);
        }
        return mx;
    }

}