#include <bits/stdc++.h>
using namespace std;
const int N = 4000;
int n, m, a[N][N], cnt;
queue<pair<int, int>> q[5];
bool mark[N][N];
int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, -1, 1};
bool is_valid(int x, int y) {
return x >= 0 && y >= 0 && x < n && y < m && !mark[x][y];
}
void add_adj(int x, int y) {
if (mark[x][y]) return;
cnt++;
mark[x][y] = true;
for (int i = 0; i < 4; i++) {
int X = x + dx[i], Y = y + dy[i];
if (is_valid(X, Y))
q[a[X][Y]].push({X, Y});
}
}
void input() {
cin >> n >> m;
for (int i = 0; i < n; i++) {
string s;
cin >> s;
for (int j = 0; j < m; j++)
a[i][j] = 2 * (s[j] == '.') + (s[j] == 'F');
}
}
void solve() {
q[a[0][0]].push({0, 0});
int ans = 0;
for (int i = 0; i < n; i++)
for (int j = 0; j < m; j++)
if (a[i][j] == 2) {
mark[i][j] = true;
cnt++;
}
for (int i = 0; cnt < n * m; i ^= 1) {
int b = a[0][0] ^ i;
while (!q[b].empty()) {
add_adj(q[b].front().first, q[b].front().second);
q[b].pop();
}
ans++;
}
cout << ans;
}
int main() {
ios:: sync_with_stdio(0), cin.tie(0), cout.tie(0);
input();
solve();
}
