#include<iostream>
#include<vector>
#include<queue>
using namespace std;
#define gecmio_ulan cin.tie(0);ios_base::sync_with_stdio(false);
int n, m;
int explored = 0;
int mat[4005][4005];
queue<pair<int, int> > a;
void dfs(int y, int x, int type) {
if (x >= m || y >= n || x < 0 || y < 0) return;
if (mat[y][x] == 2) return;
if (mat[y][x] != type) {
a.push({y, x});
return;
}
explored++;
mat[y][x] = 2;
dfs(y + 1, x, type);
dfs(y - 1, x, type);
dfs(y, x + 1, type);
dfs(y, x - 1, type);
}
int main() {
gecmio_ulan
cin >> n >> m;
char c;
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
cin >> c;
if (c == 'R') {
mat[i][j] = 0;
}
else if (c == 'F') {
mat[i][j] = 1;
}
else {
mat[i][j] = 2;
explored++;
}
}
}
int ans = 0;
bool cur;
if (mat[0][0] == 0)cur = 0;
else cur = 1;
a.push({0, 0});
while (explored != m * n) {
while (a.size()) {
pair<int, int> tmp = a.front();
a.pop();
if (mat[tmp.first][tmp.second] == 2) continue;
else if (mat[tmp.first][tmp.second] != cur) {
a.push({tmp.first, tmp.second});
break;
}
dfs(tmp.first, tmp.second, cur);
}
ans++;
cur = !cur;
}
cout << ans << "\n";
}
