JaeHyeonKim19

import java.io.*;
import java.util.*;

public class Main {
	static int [][] candies;

	static void cal(int x, int y) {
		if(x - 1 >= 0 && y - 1 >= 0) {
			int horizentalDirection = candies[x][y] + candies[x][y - 1];
			int verticalDirection = candies[x][y] + candies[x - 1][y];
			candies[x][y] = horizentalDirection > verticalDirection ? horizentalDirection : verticalDirection;
		} else if(x - 1 >= 0) {
			candies[x][y] += candies[x - 1][y];
		} else if(y - 1 >= 0) {
			candies[x][y] += candies[x][y - 1];
		}
	}

	public static void main(String[] args) throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(br.readLine());
		int n = Integer.parseInt(st.nextToken());
		int m = Integer.parseInt(st.nextToken());
		candies = new int [n][m];
		for(int i = 0; i < n; i++) {
			st = new StringTokenizer(br.readLine());
			for(int j = 0; j < m; j++) {
				candies[i][j] = Integer.parseInt(st.nextToken());
			}
		}
		for(int i = 0; i < n; i++) {
			for(int j = 0; j < m; j++) {
				cal(i, j);
			}
		}
		System.out.print(candies[n - 1][m - 1]);
	}
}