#include <bits/stdc++.h>
using namespace std;
#define int long long
#define endl "\n"
#define pb push_back
#define ff first
#define ss second
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
int dx[4] = {0,-1,0,1};
int dy[4] = {-1,0,1,0};
void solve(){
int n,m;
cin >> n >> m;
string grid[n];
vector<vector<int>> vis(n,vector<int> (m));
for(int i = 0; i < n; i++){
cin >> grid[i];
for(int j = 0; j < m; j++){
if(grid[i][j] == '*'){
vis[i][j] = 1;
}
}
}
auto check = [&](int x,int y){
if(x < 0 || x >= n || y >= m || y < 0) return false;
return !vis[x][y];
};
char c = grid[0][0]; int ans = 0;
queue<pair<int,int>> q,nw; q.push({0,0});
while(q.size()){
while(q.size()){
auto[x,y] = q.front(); q.pop();
for(int i = 0; i < 4; i++){
int curx = dx[i] + x,cury = dy[i] + y;
if(check(curx,cury)){
if(grid[curx][cury] == c) q.push({curx,cury});
else nw.push({curx,cury});
vis[curx][cury] = 1;
}
}
}
q = nw; ans++; while(nw.size()) nw.pop();
c = (c == 'T' ? 'B' : 'T');
}
cout << ans << endl;
}
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
int t = 1;
// cin >> t;
while(t--)
solve();
return 0;
}
