#include<stdio.h>
#define max(a,b)	(a>b?a:b)
int m,n;
int a[110][110];
int main()
{
	scanf("%d %d",&m,&n);
	for(int i=1;i<=m;i++)
	for(int j=1;j<=n;j++)
	scanf("%d",&a[i][j]);
	for(int i=1;i<=m;i++)
	for(int j=1;j<=n;j++)
	a[i][j]=max(a[i-1][j],a[i][j-1])+a[i][j];
	printf("%d",a[m][n]);
	return 0;
}
/**************************************************************
	Problem: 1298
	User: admin
	Language: C
	Result: Accepted
	Time:11 ms
	Memory:1192 kb
****************************************************************/