#pragma GCC optimize("Ofast")
#include<bits/stdc++.h>
#define ii pair<int, int>
#define fi first
#define se second
using namespace std;
int m, n, a[1005][15], hang[1005][15], cot[1005][15], M, N, mat[10005], dem = 0, tmp = 0;
bool d[10005], mark[10005][10005];
bool ghep (int i) {
if (d[i]) return false;
d[i] = 1;
for (int j = 1; j <= N; j++) {
if (mark[i][j])
if (!mat[j] || ghep(mat[j])) {
mat[j] = i;
return true;
}
}
return false;
}
signed main () {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> m >> n;
for (int i = 1; i <= m; i++) for (int j = 1; j <= n; j++) {
char c; cin >> c;
a[i][j] = (c == '.'); tmp += !a[i][j];
}
for (int i = 1; i <= m; i++) {
for (int j = 1; j < n; j++) {
if (!a[i][j] && !a[i][j + 1]) {
hang[i][j] = ++M;
}
}
}
for (int j = 1; j <= n; j++) {
for (int i = 1; i < m; i++)
if (!a[i][j] && !a[i + 1][j]) {
cot[i][j] = ++N;
}
}
for (int i = 1; i <= m; i++)
for (int j = 1; j <= n; j++) {
if (i < m && j < n && hang[i][j] && cot[i][j]) {
mark[hang[i][j]][cot[i][j]] = 1;
}
if (j < n && i > 1 && hang[i][j] && cot[i - 1][j]) {
mark[hang[i][j]][cot[i - 1][j]] = 1;
}
if (j > 1 && i > 1 && hang[i][j - 1] && cot[i - 1][j]) {
mark[hang[i][j - 1]][cot[i - 1][j]] = 1;
}
if (i < m && j > 1 && hang[i][j - 1] && cot[i][j]) {
mark[hang[i][j - 1]][cot[i][j]] = 1;
}
}
for (int i = 1; i <= M; i++) {
for (int j = 1; j <= N; j++) d[j] = 0;
dem += ghep(i);
}
cout << tmp - (M + N - dem);
}
