[Gold 5] 14500번 테트로미노

import java.io.*;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] arr = br.readLine().split(" ");
        int n = Integer.parseInt(arr[0]);
        int m = Integer.parseInt(arr[1]);
        int[][] paper = new int[n+1][m+1];
        int temp = 0;
        int ans = 0;
        
        for(int i=1; i<=n; i++) {
            String[] s = br.readLine().split(" ");
            for(int j=1; j<=m; j++) { paper[i][j] = Integer.parseInt(s[j-1]); }
        }
        
        //blue: 1*4
        for(int i=1; i<=n; i++) {
            for(int j=1; j<=m-3; j++) {
                temp = paper[i][j]+paper[i][j+1]+paper[i][j+2]+paper[i][j+3];
                ans = Math.max(ans, temp);
            }
        }
        
        //blue: 4*1
        for(int i=1; i<=n-3; i++) {
            for(int j=1; j<=m; j++) {
                temp = paper[i][j]+paper[i+1][j]+paper[i+2][j]+paper[i+3][j];
                ans = Math.max(ans, temp);
            }
        }
        
        //yellow
        for(int i=1; i<=n-1; i++) {
            for(int j=1; j<=m-1; j++) {
                temp = paper[i][j]+paper[i+1][j]+paper[i][j+1]+paper[i+1][j+1];
                ans = Math.max(ans, temp);
            }
        }
        
        //pink: 위&아래
        for(int i=1; i<=n-1; i++) {
            for(int j=1; j<=m-2; j++) {
                temp = paper[i][j+1]+paper[i+1][j]+paper[i+1][j+1]+paper[i+1][j+2];
                ans = Math.max(ans, temp);
                
                temp = paper[i][j]+paper[i][j+1]+paper[i][j+2]+paper[i+1][j+1];
                ans = Math.max(ans, temp);
            }
        }
        
        //pink: 오른쪽&왼쪽
        for(int i=1; i<=n-2; i++) {
            for(int j=1; j<=m-1; j++) {
                temp = paper[i][j]+paper[i+1][j]+paper[i+1][j+1]+paper[i+2][j];
                ans = Math.max(ans, temp);
                
                temp = paper[i][j+1]+paper[i+1][j]+paper[i+1][j+1]+paper[i+2][j+1];
                ans = Math.max(ans, temp);
            }
        }
        
        //green : 1&2
        for(int i=1; i<=n-2; i++) {
            for(int j=1; j<=m-1; j++) {
                temp = paper[i][j]+paper[i+1][j]+paper[i+1][j+1]+paper[i+2][j+1];
                ans = Math.max(ans, temp);
                
                temp = paper[i][j+1]+paper[i+1][j]+paper[i+1][j+1]+paper[i+2][j];
                ans = Math.max(ans, temp);
            }
        }
        
        //green : 3&4
        for(int i=1; i<=n-1; i++) {
            for(int j=1; j<=m-2; j++) {
                temp = paper[i+1][j]+paper[i+1][j+1]+paper[i][j+1]+paper[i][j+2];
                ans = Math.max(ans, temp);
                
                temp = paper[i][j]+paper[i][j+1]+paper[i+1][j+1]+paper[i+1][j+2];
                ans = Math.max(ans, temp);
            }
        }
        
        //orange: 1&2&3&4
        for(int i=1; i<=n-2; i++) {
            for(int j=1; j<=m-1; j++) {
                temp = paper[i][j]+paper[i+1][j]+paper[i+2][j]+paper[i+2][j+1];
                ans = Math.max(ans, temp);
                
                temp = paper[i][j]+paper[i+1][j]+paper[i+2][j]+paper[i][j+1];
                ans = Math.max(ans, temp);
                
                temp = paper[i][j+1]+paper[i+1][j+1]+paper[i+2][j+1]+paper[i+2][j];
                ans = Math.max(ans, temp);
                
                temp = paper[i][j]+paper[i][j+1]+paper[i+1][j+1]+paper[i+2][j+1];
                ans = Math.max(ans, temp);
            }
        }
        
        //orange: 5&6&7&8
        for(int i=1; i<=n-1; i++) {
            for(int j=1; j<=m-2; j++) {
                temp = paper[i][j]+paper[i+1][j]+paper[i][j+1]+paper[i][j+2];
                ans = Math.max(ans, temp);
                
                temp = paper[i][j]+paper[i][j+1]+paper[i][j+2]+paper[i+1][j+2];
                ans = Math.max(ans, temp);
                
                temp = paper[i][j]+paper[i+1][j]+paper[i+1][j+1]+paper[i+1][j+2];
                ans = Math.max(ans, temp);
                
                temp = paper[i+1][j]+paper[i+1][j+1]+paper[i+1][j+2]+paper[i][j+2];
                ans = Math.max(ans, temp);
            }
        }
        
        System.out.println(ans);
    }
}