package quki.algorithm.dp;

import java.util.Scanner;

/**

* À̵¿Çϱâ

*

* @author quki

*/

public class BOJ11048 {

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

int n = sc.nextInt();

int m = sc.nextInt();

int a[][] = new int[n + 1][m + 1];

int d[][] = new int[n + 1][m + 1];

for (int i = 1; i <= n; i++) {

for (int j = 1; j <= m; j++) {

a[i][j] = sc.nextInt();

}

}

for (int i = 1; i <= n; i++) {

for (int j = 1; j <= m; j++) {

int max = Math.max(d[i - 1][j - 1], d[i - 1][j]);

d[i][j] = Math.max(max, d[i][j - 1]) + a[i][j];

}

}

System.out.println(d[n][m]);

}

}