#include <iostream>
#include <vector>
#include <queue>
using namespace std;
struct heap {
int i, j, w;
bool operator < (const heap &o) const {
return w > o.w;
}
};
vector<pair<int, int>> dir = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
int n, m;
cin >> n >> m;
vector<string> grid(n);
for (auto &s:grid) cin >> s;
auto invalid = [&](int i, int j) -> bool {
return i < 0 || i >= n || j < 0 || j >= m;
};
priority_queue<heap> pq;
vector<vector<bool>> vis(n, vector<bool>(m, false));
pq.push({0, 0, grid[0][0] == 'F'});
while (!pq.empty()){
auto [i, j, W] = pq.top(); pq.pop();
if (vis[i][j]) continue;
vis[i][j] = true;
if (i == n - 1 && j == m - 1){
cout << W + 1 << '\n';
return 0;
}
for (auto [di, dj]:dir){
if (invalid(i + di, j + dj)) continue;
pq.push({i + di, j + dj, W + (grid[i][j] != grid[i + di][j + dj])});
}
}
}
