#include <cmath>
#include <iostream>
using namespace std;
int n, m, matr[110][110], maxsum[110][110];
int main()
{
	cin >> n >> m;
	for (int i = 1; i <= n; i++)
		for (int j = 1; j <= m; j++)
			cin >> matr[i][j];
	maxsum[1][1] = matr[1][1];
	for (int i = 1; i <= n; i++)
		for (int j = 1; j <= m; j++)
			maxsum[i][j] = matr[i][j] + max(maxsum[i - 1][j], maxsum[i][j - 1]);
	cout << maxsum[n][m];
	return 0;
}