#include <iostream>
#include <vector>
#include <queue>
#define endl '\n'
#define pb emplace_back
#define front back
#define pop pop_back
#define push emplace_back
#define fr first
#define sc second
#define mp make_pair
using namespace std;
typedef pair<int, int> pi;
int n, h, w;
const int MAXN = 4010;
string mat[4010];
vector<pi> q[2];
bool used[MAXN][MAXN];
int x[4] = {1, 0, -1, 0};
int y[4] = {0, -1, 0, 1};
int main(){
ios::sync_with_stdio(0);cin.tie(0);
cin >> h >> w;
for(int i=0; i<h; i++) cin >> mat[i];
int p, cnt = 0;
used[0][0] = 1;
p = (mat[0][0] == 'F');
q[p].pb(mp(0, 0));
while(!q[0].empty() || !q[1].empty()){
while(!q[p].empty()){
pi v = q[p].front();
q[p].pop();
for(int i=0; i<4; i++){
pi u = mp(v.fr+x[i], v.sc+y[i]);
if(u.fr == -1 || u.sc == -1 || u.fr == h || u.sc == w || mat[u.fr][u.sc] == '.') continue;
if(used[u.fr][u.sc]) continue;
bool tp = (mat[u.fr][u.sc] == 'F');
q[tp].push(u);
used[u.fr][u.sc] = 1;
}
}
p ^= 1;
cnt++;
}
cout << cnt << endl;
return 0;
}
