#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, m;
cin >> n >> m;
vector<vector<char>> mat(n, vector<char>(m));
for (int i = 0; i < n; ++i) {
for (int j = 0; j < m; ++j) {
cin >> mat[i][j];
}
}
int ans = 1;
vector<vector<char>> right(n, vector<char>(m, 0));
vector<vector<char>> left(n, vector<char>(m, 0));
left[0][0] = (mat[0][0] != '#');
for (int i = 0; i < n; ++i) {
for (int j = 0; j < m; ++j) {
if (mat[i][j] == '#')
continue;
if (i && left[i - 1][j])
left[i][j] = 1;
if (j && left[i][j - 1])
left[i][j] = 1;
}
}
right[n - 1][m - 1] = (mat[n - 1][m - 1] != '#');
for (int i = n - 1; ~i; --i) {
for (int j = m - 1; ~j; --j) {
if (mat[i][j] == '#')
continue;
if (i + 1 < n && right[i + 1][j])
right[i][j] = 1;
if (j + 1 < m && right[i][j + 1])
right[i][j] = 1;
}
}
vector<vector<char>> good(n, vector<char>(m));
for (int i = 0; i < n; ++i) {
for (int j = 0; j < m; ++j) {
good[i][j] = left[i][j] && right[i][j];
}
}
if (!good[0][0]) {
cout << 0;
return 0;
}
int dx[] = {-1, -1, -1, 0, 0, 1, 1, 1};
int dy[] = {-1, 0, 1, -1, 1, 1, 0, -1};
vector<vector<char>> visited(n, vector<char>(m, 0));
for (int i = 0; i < n; ++i) {
for (int j = 0; j < m; ++j) {
if (good[i][j] || visited[i][j])
continue;
queue<pair<int, int>> qu;
qu.push({i, j});
visited[i][j] = 1;
int t = (!i || !j || i == n - 1 || j == m - 1);
while (qu.size()) {
auto [x, y] = qu.front();
qu.pop();
for (int d = 0; d < 8; ++d) {
int nx = x + dx[d], ny = y + dy[d];
if (min(nx, ny) < 0 || nx >= n || ny >= m || visited[nx][ny] ||
good[nx][ny])
continue;
visited[nx][ny] = 1;
if (!nx || !ny || nx == n - 1 || ny == m - 1)
t = 1;
qu.push({nx, ny});
}
}
ans += !t;
}
}
cout << ans;
return 0;
}
