from itertools import combinations
from collections import deque
import copy
import sys
input = sys.stdin.readline

N, M = map(int, input().split())
all_axis: list[tuple[int, int]] = []
lab_origin: list[list[int]] = []
virus: list[tuple[int, int]] = []

for i in range(N) :
    lab_origin.append(list(map(int, input().split())))
    for j in range(M) :
        if lab_origin[i][j] == 2 :
            virus.append((i,j))
        elif lab_origin[i][j] != 1 :
            all_axis.append((i,j))

maxArea = 0
dx = [-1,1,0,0]
dy = [0,0,-1,1]

for wall_comb in combinations(all_axis, 3) :
    lab_copy = copy.deepcopy(lab_origin)
    
    for y, x in  wall_comb:
        lab_copy[y][x] = 1
    
    q = deque()
    for v in virus :
        q.append(v)

    while q :
        cy, cx = q.popleft()
        
        for i in range(4) :
            ny, nx = cy + dy[i], cx + dx[i]
            
            if 0<=ny<N and 0<=nx<M and lab_copy[ny][nx] == 0 :
                q.append((ny,nx))
                lab_copy[ny][nx] = 2
    
    currentArea = 0
    for i in range(N) :
        currentArea += lab_copy[i].count(0)
    
    maxArea = max(maxArea, currentArea)

print(maxArea)