#include <bits/stdc++.h>
using namespace std;
vector<vector<char>> grid(4001, vector<char>(4001));
vector<vector<bool>> visited(4001, vector<bool>(4001, false));
vector<pair<int, int>> delta = {{-1, 0}, {0, -1}, {1, 0}, {0, 1}};
map<char, char> hm;
int n, m, steps = 0;
bool inBounds(int i, int j) {
if (i < 0 || i >= n || j < 0 || j >= m) return 0;
return 1;
}
void bfs() {
int i = n-1, j = m-1;
queue<pair<int, int>> q;
q.push({i, j});
vector<vector<bool>> bfsVisited(n, vector<bool>(m, false));
bfsVisited[i][j] = true;
while (!q.empty()) {
int currRow = q.front().first;
int currCol = q.front().second;
grid[currRow][currCol] = hm[grid[currRow][currCol]];
if (!visited[currRow][currCol]) {
visited[currRow][currCol] = true;
steps--;
}
q.pop();
for (int i = 0; i < 4; i++) {
int nextRow = currRow + delta[i].first;
int nextCol = currCol + delta[i].second;
if (inBounds(nextRow, nextCol)
&& !bfsVisited[nextRow][nextCol]
&& grid[nextRow][nextCol] != '.'
&& grid[nextRow][nextCol] != grid[currRow][currCol]) {
q.push({nextRow, nextCol});
bfsVisited[nextRow][nextCol] = true;
}
}
}
}
int main() {
cin >> n >> m;
hm['F'] = 'R';
hm['R'] = 'F';
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
cin >> grid[i][j];
if (grid[i][j] == '.') visited[i][j] = true;
else steps++;
}
}
int animals = 0;
while (steps > 0) {
animals++;
bfs();
}
cout << animals << "\n";
return 0;
}
