#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ll long long
#define ld long double
#define ull unsigned long long
#define ff first
#define ss second
#define pii pair<int,int>
#define pll pair<long long, long long>
#define vi vector<int>
#define vl vector<long long>
#define pb push_back
#define rep(i, b) for(int i = 0; i < (b); ++i)
#define rep2(i,a,b) for(int i = a; i <= (b); ++i)
#define rep3(i,a,b,c) for(int i = a; i <= (b); i+=c)
#define count_bits(x) __builtin_popcountll((x))
#define all(x) (x).begin(),(x).end()
#define siz(x) (int)(x).size()
#define forall(it,x) for(auto& it:(x))
using namespace __gnu_pbds;
using namespace std;
typedef tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update> ordered_set;
//mt19937 mt;void random_start(){mt.seed(chrono::time_point_cast<chrono::milliseconds>(chrono::high_resolution_clock::now()).time_since_epoch().count());}
//ll los(ll a, ll b) {return a + (mt() % (b-a+1));}
const int INF = 1e9+50;
const ll INF_L = 1e18+40;
const ll MOD = 1e9+7;
int dp[445][445][2][2];
int rep_[445];
int siz_[445];
bool is_path[445];
int sides[445];
int fint(int v)
{
if(rep_[v] == v) return v;
rep_[v] = fint(rep_[v]);
return rep_[v];
}
void onion(int a, int b)
{
a = fint(a);
b = fint(b);
if(a == b) return;
siz_[b] += siz_[a];
rep_[a] = b;
is_path[b] = is_path[b] || is_path[a];
}
int main()
{
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
//random_start();
int n,m;
cin >> n >> m;
rep(i,n*m)
{
rep_[i] = i;
siz_[i] = 1;
}
rep(i,n+1)
{
rep(j,m)
{
char z;
cin >> z;
if(z == '1')
{
if(i!=n)
{
sides[i*m+j]++;
}
if(i!=0)
{
sides[(i-1)*m+j]++;
}
}
else
{
if(i > 0 && i < n)
{
onion(i*m+j,(i-1)*m+j);
}
if(i == 0)
{
is_path[fint(i*m+j)] = 1;
}
if(i == n)
{
is_path[fint((i-1)*m+j)] = 1;
}
}
}
}
rep(i,n)
{
rep(j,m+1)
{
char z;
cin >> z;
if(z == '1')
{
if(j!=n)
{
sides[i*m+j]++;
}
if(j!=0)
{
sides[i*m+j-1]++;
}
}
else
{
if(j > 0 && j < m)
{
onion(i*m+j,i*m+j-1);
}
if(j == 0)
{
is_path[fint(i*m+j)] = 1;
}
if(j == m)
{
is_path[fint(i*m+j-1)] = 1;
}
}
}
}
vector<int> paths;
vector<int> cycles;
rep(i,n*m)
{
if(fint(i) == i && sides[i] != 4)
{
if(is_path[i])
{
paths.pb(siz_[i]);
}
else
{
cycles.pb(siz_[i]);
}
}
}
sort(all(paths));
sort(all(cycles));
for(int p = siz(paths); p >= 0; p--)
{
//cout << comps[i] << " comps\n";
for(int c = siz(cycles); c >= 0; c--)
{
if(p == siz(paths) && c == siz(cycles))
{
continue;
}
dp[p][c][0][0] = -1e5;
dp[p][c][0][1] = -1e5;
dp[p][c][1][0] = 1e5;
dp[p][c][1][1] = 1e5;
if(p < siz(paths))
{
// 0 0
if(p == siz(paths)-1 && c == siz(cycles)) dp[p][c][0][0] = paths[p];
if(p+1 < siz(paths))
{
dp[p][c][0][0] = max(dp[p][c][0][0],dp[p+1][c][1][0] + paths[p]);
}
if(c < siz(cycles))
{
dp[p][c][0][0] = max(dp[p][c][0][0],dp[p+1][c][1][1] + paths[p]);
}
if(paths[p] > 2)
{
int w2 = 1e5;
if(p + 1 < siz(paths))
{
w2 = min(w2,dp[p+1][c][0][0]);
}
if(c < siz(cycles))
{
w2 = min(w2,dp[p+1][c][0][1]);
}
if(w2 != 1e5)
dp[p][c][0][0] = max(dp[p][c][0][0],w2 + paths[p] - 4);
}
//1 0
if(p == siz(paths)-1 && c == siz(cycles)) dp[p][c][1][0] = -paths[p];
if(p + 1 < siz(paths))
{
dp[p][c][1][0] = min(dp[p][c][1][0],dp[p+1][c][0][0] - paths[p]);
}
if(c < siz(cycles))
{
dp[p][c][1][0] = min(dp[p][c][1][0],dp[p+1][c][0][1] - paths[p]);
}
if(paths[p] > 2)
{
int w2 = -1e5;
if(p + 1 < siz(paths))
{
w2 = max(w2,dp[p+1][c][1][0]);
}
if(c < siz(cycles))
{
w2 = max(w2,dp[p+1][c][1][1]);
}
if(w2 != -1e5)
dp[p][c][1][0] = min(dp[p][c][1][0],w2 - paths[p] + 4);
}
}
if(c < siz(cycles))
{
// 0 1
if(c == siz(cycles)-1 && p == siz(paths)) dp[p][c][0][1] = cycles[c];
if(p < siz(paths))
{
dp[p][c][0][1] = max(dp[p][c][0][1],dp[p][c+1][1][0]+cycles[c]);
}
if(c + 1 < siz(cycles))
{
dp[p][c][0][1] = max(dp[p][c][0][1],dp[p][c+1][1][1]+cycles[c]);
}
int w2 = 2e5;
if(p < siz(paths))
{
w2 = min(w2,dp[p][c+1][0][0]);
}
if(c + 1 < siz(cycles))
{
w2 = min(w2,dp[p][c+1][0][1]);
}
if(w2 != 2e5)
dp[p][c][0][1] = max(dp[p][c][0][1],w2 + cycles[c] - 8);
// 1 1
if(c == siz(cycles)-1 && p == siz(paths)) dp[p][c][1][1] = -cycles[c];
if(p < siz(paths))
{
dp[p][c][1][1] = min(dp[p][c][1][1],dp[p][c+1][0][0]-cycles[c]);
}
if(c + 1 < siz(cycles))
{
dp[p][c][1][1] = min(dp[p][c][1][1],dp[p][c+1][0][1]-cycles[c]);
}
w2 = -2e5;
if(p < siz(paths))
{
w2 = max(w2,dp[p][c+1][1][0]);
}
if(c + 1 < siz(cycles))
{
w2 = max(w2,dp[p][c+1][1][1]);
}
if(w2 != -2e5)
dp[p][c][1][1] = min(dp[p][c][1][1],w2 - cycles[c] + 8);
}
// cout << "paths: " << p << " cycles: " << c << "\n";
// cout << dp[p][c][0][0] << " 00\n";
// cout << dp[p][c][0][1] << " 01\n";
// cout << dp[p][c][1][0] << " 10\n";
// cout << dp[p][c][1][1] << " 11\n\n";
}
}
//cout << siz(paths) << " " << siz(cycles) << " " << cycles[0] << " sizy\n";
if(siz(paths) == 0 && siz(cycles) == 0)
{
cout << 0;
return 0;
}
cout << max((siz(paths) != 0 ? dp[0][0][1][0] : (int)-2e5),(siz(cycles) != 0 ? dp[0][0][1][1]: (int)-2e5)) << "\n";
}
