import java.util.*;
public class Main {
//테트로미노
static int[][][] BLOCKS_14500 = {
//19 4 2
{{0,0}, {0,1}, {0,2}, {0,3}}
,{{0,0}, {1,0}, {2,0}, {3,0}}
,{{0,0}, {1,0}, {0,1}, {1,1}}
,{{0,0}, {0,1}, {0,2}, {1,2}}
,{{0,0}, {1,0}, {2,0}, {0,1}}
,{{0,0}, {1,0}, {1,1}, {1,2}}
,{{2,0}, {0,1}, {1,1}, {2,1}}
,{{1,0}, {1,1}, {1,2}, {0,2}}
,{{0,0}, {0,1}, {1,1}, {2,1}}
,{{0,0}, {1,0}, {0,1}, {0,2}}
,{{0,0}, {1,0}, {2,0}, {2,1}}
,{{0,0}, {1,0}, {2,0}, {1,1}}
,{{1,0}, {0,1}, {1,1}, {1,2}}
,{{0,1}, {1,0}, {1,1}, {2,1}}
,{{0,0}, {0,1}, {0,2}, {1,1}}
,{{0,0}, {0,1}, {1,1}, {1,2}}
,{{0,1}, {1,1}, {1,0}, {2,0}}
,{{1,0}, {1,1}, {0,1}, {0,2}}
,{{0,0}, {1,0}, {1,1}, {2,1}}
};
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
int m = sc.nextInt();
int[][] a = new int[n][m];
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
a[i][j] = sc.nextInt();
}
}
int ans = 0;
//전체 블록을 지정
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
//4개의 큐브로 이루어진 도형 19개를 확인
for (int k = 0; k < 19; k++) {
boolean ok = true;
//큐브의 값
int sum = 0;
for (int l = 0; l < 4; l++) {
//큐브의 x좌표
int x = i + BLOCKS_14500[k][l][0];
//큐브의 y좌표
int y = j + BLOCKS_14500[k][l][1];
//큐브 4개의 값을 모두 구한다
if (x >= 0 && x < n && y >= 0 && y < m) {
//큐브의 값 = a[x][y]
sum += a[x][y];
} else {
ok = false;
break;
}
}
if (ok && ans < sum ) ans = sum;
}
}
}
sc.close();
System.out.println(ans);
}
}
