import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }

string COLOR(string s = "") { return "\x1b[" ~ s ~ "m"; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }




void main() {
  try {
    for (; ; ) {
      const M = readInt;
      const N = readInt;
      auto A = new int[][](M + 2, N + 2);
      foreach (x; 1 .. M + 1) foreach (y; 1 .. N + 1) {
        A[x][y] = readInt;
      }
      
      int[] xs, ys;
      foreach (x; 0 .. M + 2) foreach (y; 0 .. N + 2) {
        if (x == 0 || x == M + 1 || y == 0 || y == N + 1) {
          xs ~= x;
          ys ~= y;
        }
      }
      const len = cast(int)(xs.length);
      
      int ans;
      
      int score;
      int zeit;
      auto vis = new int[][](M + 2, N + 2);
      void go(int s, int dx, int dy) {
        for (int x = xs[s], y = ys[s]; ; ) {
          const xx = x + dx;
          const yy = y + dy;
          if (!(1 <= xx && xx <= M && 1 <= yy && yy <= N)) {
            break;
          }
          x = xx;
          y = yy;
          if (vis[x][y] != zeit) {
            vis[x][y] = zeit;
            score += A[x][y];
          }
        }
      }
      bool isGood(int s, int dx, int dy) {
        const x = xs[s];
        const y = ys[s];
        const xx = x + dx;
        const yy = y + dy;
        return (1 <= xx && xx <= M && 1 <= yy && yy <= N);
      }
      
      foreach (s0; 0 .. len) foreach (dx0; -1 .. +1 + 1) foreach (dy0; -1 .. +1 + 1) if (dx0 || dy0)
      foreach (s1; 0 .. len) foreach (dx1; -1 .. +1 + 1) foreach (dy1; -1 .. +1 + 1) if (dx1 || dy1)
      {
        if ([s0, dx0, dy0] > [s1, dx1, dy1]) continue;
        if (!isGood(s0, dx0, dy0)) continue;
        if (!isGood(s1, dx1, dy1)) continue;
        ++zeit;
        score = 0;
        go(s0, dx0, dy0);
        go(s1, dx1, dy1);
// if([xs[s0],ys[s0],dx0,dy0,xs[s1],ys[s1],dx1,dy1]==[0,2,1,0,0,3,1,0])writeln(vis," ",score);
        chmax(ans, score);
      }
      writeln(ans);
    }
  } catch (EOFException e) {
  }
}