#include <bits/stdc++.h>
using namespace std;
#define fast ios::sync_with_stdio(0);cin.tie(0);
typedef long long ll;
#define f first
#define s second
#define MOD 1000000007
#define LOGN 20
#define MAXN 1000005
const int delRow[] = {-1, 0, 0, 1};
const int delCol[] = {0, -1, 1, 0};
vector<vector<int>> grid;
int main() {
fast
int H, W;
cin >> H >> W;
grid = vector<vector<int>>(H+1, vector<int>(W+1));
for (int i = 1; i <= H; i++) {
string s;
cin >> s;
for (int j = 1; j <= W; j++) {
if (s[j-1] == '.')
grid[i][j] = -1;
else if (s[j-1] == 'F')
grid[i][j] = 0;
else
grid[i][j] = 1;
}
}
vector<vector<int>> vis(H+1, vector<int>(W+1, false));
queue<pair<int,int>> q, new_q;
q.push({1,1});
int cnt = 1;
while (!q.empty()) {
int row = q.front().f;
int col = q.front().s;
q.pop();
vis[row][col] = true;
for (int i = 0; i < 4; i++) {
int nRow = delRow[i] + row;
int nCol = delCol[i] + col;
if (nRow >= 1 && nCol >= 1 && nRow <= H && nCol <= W && !vis[nRow][nCol] && grid[nRow][nCol] != -1) {
if (grid[nRow][nCol] == grid[row][col])
q.push({nRow, nCol});
else
new_q.push({nRow, nCol});
}
}
if (q.empty() && !new_q.empty()) {
q = new_q;
cnt++;
new_q = queue<pair<int,int>>();
}
}
cout << cnt << "\n";
}
