#include <bits/stdc++.h>
using namespace std;

const int INF = 1e9;
int dr[] = {-1, 1, 0, 0}; // 0: Up, 1: Down, 2: Left, 3: Right
int dc[] = {0, 0, -1, 1};

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int r, c;
    if (!(cin >> r >> c)) return 0;
    vector<string> grid(r);
    for (int i = 0; i < r; i++) {
        cin >> grid[i];
    }
    vector<vector<int>> dist(r, vector<int>(c, INF));
    deque<pair<int, int>> dq;
    dist[0][0] = 0;
    dq.push_back({0, 0});
    while (!dq.empty()) {
        auto [cr, cc] = dq.front();
        dq.pop_front();
        for (int i = 0; i < 4; i++) {
            int nr = cr + dr[i];
            int nc = cc + dc[i];
            if (nr >= 0 && nr < r && nc >= 0 && nc < c) {
                int w;
                if (grid[cr][cc] == 'H') {
                    // Left/Right is 0, Up/Down is 1
                    w = (i >= 2) ? 0 : 1;
                } else {
                    // Up/Down is 0, Left/Right is 1
                    w = (i < 2) ? 0 : 1;
                }
                if (dist[cr][cc] + w < dist[nr][nc]) {
                    dist[nr][nc] = dist[cr][cc] + w;
                    if (w == 0) {
                        dq.push_front({nr, nc});
                    } else {
                        dq.push_back({nr, nc});
                    }
                }
            }
        }
    }
    cout << dist[r-1][c-1] << "\n";
    return 0;
}