#include<bits/stdc++.h>
using namespace std;
int a[105][105];
int main()
{
	int m;
	int n;
	cin>>m>>n;
	for(int i=1;i<=m;i++)
	{
		for(int j=1;j<=n;j++)
		{
			cin>>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]);
		}
	}
	cout<<a[m][n];
	return 0;
}
/**************************************************************
	Problem: 1298
	User: chenkexin
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2116 kb
****************************************************************/