#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
// #pragma GCC optimize ("Ofast,unroll-loops")
// #pragma GCC target ("avx,avx2,fma")
using namespace std;
using namespace __gnu_pbds;
typedef int ll;
typedef long double ld;
typedef pair <ll, ll> pll;
#ifdef SINA
#define dbg(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1> void __f(const char* name, Arg1&& arg1) { cout << name << " : " << arg1 << std::endl; }
template <typename Arg1, typename... Args> void __f (const char* names, Arg1&& arg1, Args&&... args) {
const char* comma = strchr(names + 1, ',');cout.write(names, comma - names) << " : " << arg1<<" | ";__f(comma+1, args...); }
#define dbg2(x, j, n) cout<< #x << " : "; output((j), (n), x, 1);
#else
#define dbg(...) 0
#define dbg2(x, j, n) 0
#endif
#define SZ(x) ((ll)((x).size()))
#define File(s, t) freopen(s ".txt", "r", stdin); freopen(t ".txt", "w", stdout);
#define input(j, n, a) for (int _i = (j); _i < (n)+(j); _i++) cin>> a[_i];
#define output(j, n, a, t) for (int _i = (j); _i < (n)+(j); _i++) cout<< a[_i] << (((t) && _i != (n)+(j)-1)? ' ' : '\n');
#define kill(x) return cout<< x << endl, 0
#define cl const ll
#define fr first
#define sc second
#define lc (v << 1)
#define rc (lc | 1)
#define mid ((l + r) >> 1)
#define All(x) (x).begin(), (x).end()
const long long inf = 1e18;
cl mod = 1e9 + 7, MOD = 998244353;
template <class A, class B> ostream& operator << (ostream& out, const pair<A, B> &a) {
return out << '(' << a.first << ", " << a.second << ')'; }
template <class A> ostream& operator << (ostream& out, const vector<A> &a) {
if(!a.size())return cout<<"[]";cout<< '[' << a[0]; for (int i = 0; ++i < (int)(a.size());) cout<< ", " << a[i];cout<< ']'; }
template <class T, typename _t = less <T> > using Tree = tree <T, null_type, _t, rb_tree_tag, tree_order_statistics_node_update>;
cl N = 1e3 + 3;
ll ans, n, m, k;
pll dir [4] = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
char c [N][N], T [2] = {'T', 'B'};
vector <pll> lev [2];
bool mark [N][N];
void bfs (ll x, ll y) {
// dbg(mark[1][4]);
// dbg(x, y);
for (ll i = 0; i < SZ(lev[x]); i++) for (ll j = 0; j < 4; j++) {
if (!mark[lev[x][i].fr + dir[j].fr][lev[x][i].sc + dir[j].sc]&&c[lev[x][i].fr + dir[j].fr][lev[x][i].sc + dir[j].sc]==T[y]){
mark[lev[x][i].fr + dir[j].fr][lev[x][i].sc + dir[j].sc] = 1;
lev[y].push_back({lev[x][i].fr + dir[j].fr, lev[x][i].sc + dir[j].sc});
}
}
x = y;
for (ll i = 0; i < SZ(lev[x]); i++) for (ll j = 0; j < 4; j++) {
if (!mark[lev[x][i].fr + dir[j].fr][lev[x][i].sc + dir[j].sc]&&c[lev[x][i].fr + dir[j].fr][lev[x][i].sc + dir[j].sc]==T[y]){
mark[lev[x][i].fr + dir[j].fr][lev[x][i].sc + dir[j].sc] = 1;
lev[y].push_back({lev[x][i].fr + dir[j].fr, lev[x][i].sc + dir[j].sc});
}
}
if (!lev[y].empty()) ans++;
else {
cout<< ans << endl;
exit(0);
}
dbg(lev[y]);
}
int main ()
{
ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
ll i, j;
cin>> n >> m;
for (i = 0; i <= n + 1; i++) mark[i][0] = mark[i][m + 1] = 1;
for (i = 0; i <= m + 1; i++) mark[0][i] = mark[n + 1][i] = 1;
for (i = 1; i <= n; i++) for (j = 1; j <= m; j++) cin>> c[i][j];
if (c[1][1] == T[1]) k = 1;
lev[k].push_back({1, 1});
mark[1][1] = 1;
bfs(k, k);
while (1 < 2) {
bfs(k, k ^ 1);
lev[k].clear();
k ^= 1;
}
return 0;
}
/*
4 4
TT*T
*TTT
***T
***T
3 5
TTBB*
*T*B*
*TTTT
7 5
BT***
BTBBB
BTTTB
BBT*B
BBT*B
BBT**
*BBBB
*/
