#include"bits/stdc++.h"
using namespace std;
const short mxN = 4001;
int cl[mxN][mxN];
short g[mxN][mxN];
short H, W;
bool legal(short i, short j) {
return 0 <= i && 0 <= j && i < H && j < W && 2 != g[i][j];
}
int main() {
cin.tie(nullptr)->sync_with_stdio(false);
cin >> H >> W;
for (int i = 0; i < H; i ++) {
for (int j = 0; j < W; j ++) {
char c;
cin >> c;
if ('F' == c) {
g[i][j] = 1;
} else if ('.' == c) {
g[i][j] = 2;
}
}
}
priority_queue<array<int,3>> pq;
pq.push({-1, 0, 0});
cl[0][0] = -1;
int dx[] = {0, 0, 1, -1};
int dy[] = {1, -1, 0, 0};
int ans = 0;
while (!pq.empty()) {
auto [c, i, j] = pq.top();
ans = c;
pq.pop();
for (int k = 0; k < 4; k ++) {
short l = i + dx[k];
short o = j + dy[k];
if (legal(l, o) && 0 == cl[l][o]) {
if (g[l][o] == g[i][j]) {
cl[l][o] = c;
pq.push({c, l, o});
} else {
cl[l][o] = c - 1;
pq.push({c - 1, l, o});
}
}
}
}
cout << -ans << endl;
}
