/* -*- coding: utf-8 -*-
 *
 * 2509.cc:  No.2509 Beam Shateki - yukicoder
 */

#include<cstdio>
#include<algorithm>
 
using namespace std;

/* constant */

const int MAX_H = 100;
const int MAX_W = 100;

/* typedef */

/* global variables */

int as[MAX_H][MAX_W];
int hs[MAX_H], vs[MAX_W], ps[MAX_H + MAX_W], qs[MAX_H + MAX_W];

/* subroutines */

/* main */

int main() {
  int h, w;
  scanf("%d%d", &h, &w);
  int hw = h + w - 1;

  for (int i = 0; i < h; i++)
    for (int j = 0; j < w; j++) {
      scanf("%d", as[i] + j);
      hs[i] += as[i][j];
      vs[j] += as[i][j];
      ps[i + j] += as[i][j];
      qs[i + (w - 1 - j)] += as[i][j];
    }

  int maxs = 0;

  for (int i = 0; i < h; i++) {
    maxs = max(maxs, hs[i]);
    for (int i1 = i + 1; i1 < h; i1++)
      maxs = max(maxs, hs[i] + hs[i1]);
    for (int j = 0; j < w; j++)
      maxs = max(maxs, hs[i] + vs[j] - as[i][j]);
    for (int d = 0; d < hw; d++) {
      int j = d - i;
      maxs = max(maxs, hs[i] + ps[d] - ((j >= 0 && j < w) ? as[i][j] : 0));
    }
    for (int e = 0; e < hw; e++) {
      int j = i + w - 1 - e;
      maxs = max(maxs, hs[i] + qs[e] - ((j >= 0 && j < w) ? as[i][j] : 0));
    }
  }

  for (int j = 0; j < w; j++) {
    maxs = max(maxs, vs[j]);
    for (int j1 = j + 1; j1 < w; j1++)
      maxs = max(maxs, vs[j] + vs[j1]);
    for (int d = 0; d < hw; d++) {
      int i = d - j;
      maxs = max(maxs, vs[j] + ps[d] - ((i >= 0 && i < h) ? as[i][j] : 0));
    }
    for (int e = 0; e < hw; e++) {
      int i = e - (w - 1 - j);
      maxs = max(maxs, vs[j] + qs[e] - ((i >= 0 && i < h) ? as[i][j] : 0));
    }
  }

  for (int d = 0; d < hw; d++) {
    maxs = max(maxs, ps[d]);
    for (int d1 = d + 1; d1 < hw; d1++)
      maxs = max(maxs, ps[d] + ps[d1]);
    for (int e = 0; e < hw; e++) {
      // i+j=d, i+(w-1-j)=e -> 2i+(w-1)=d+e -> 2i=d+e-(w-1) -> i=(d+e-(w-1))/2
      // j = d-i=d-(d+e-(w-1))/2=(d-e+(w-1))/2
      int i2 = (d + e - (w - 1));
      if (! (i2 & 1)) {
	int i = i2 / 2, j = d - i;
	int aij = (i >= 0 && i < h && j >= 0 && j < w) ? as[i][j] : 0;
	maxs = max(maxs, ps[d] + qs[e] - aij);
      }
      else
	maxs = max(maxs, ps[d] + qs[e]);
    }
  }

  for (int e = 0; e < hw; e++) {
    maxs = max(maxs, qs[e]);
    for (int e1 = e + 1; e1 < hw; e1++)
      maxs = max(maxs, qs[e] + qs[e1]);
  }

  printf("%d\n", maxs);

  return 0;
}