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#include<iostream>
#include <algorithm>
#include <vector>
#include <queue>
using namespace std;
int dx[] = { -1,1,0,0 };
int dy[] = { 0,0,-1,1 };
int n, m;
int bfs(vector<vector<int>>arr, vector<pair<int,int>>&virus) {
queue<pair<int, int>>q;
int count = 0;
for (auto t : virus) {
q.push(t);
while (!q.empty()) {
int x = q.front().first;
int y = q.front().second;
q.pop();
for (int i = 0; i < 4; i++) {
int nx = x + dx[i];
int ny = y + dy[i];
if(nx>=0 && nx<n && ny>=0 && ny<m){
if (arr[nx][ny] == 0) {
arr[nx][ny] = 2;
q.push(make_pair(nx, ny));
}
}
}
}
}
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
if (arr[i][j] == 0) {
count++;
}
}
}
return count;
}
int main() {
vector<vector<int>>arr(9,vector<int>(9,0));
vector<pair<int, int> >virus;
cin >> n;
cin >> m;
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
cin >> arr[i][j];
if (arr[i][j] == 2) {
virus.push_back(make_pair(i, j));
}
}
}
int maxnum = 0;
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
if (arr[i][j] == 0) {
arr[i][j] = 1;
for (int k = i; k < n; k++) {
for (int t = 0; t < m; t++) {
if (arr[k][t] == 0) {
arr[k][t] = 1;
for (int l = k; l < n; l++) {
for (int s = 0; s < m; s++) {
if (arr[l][s] == 0) {
arr[l][s] = 1;
int safe = bfs(arr, virus);
maxnum = max(maxnum, safe);
arr[l][s] = 0;
}
}
}
arr[k][t] = 0;
}
}
}
arr[i][j] = 0;
}
}
}
cout<<maxnum<<endl;
return 0;
}