#include <bits/stdc++.h>
using namespace std;
#define ForUp(i, a, b) for (int i = (a), _b = (b); i <= _b; i++)
#define ForDn(i, a, b) for (int i = (a), _b = (b); i >= _b; i--)
#define all(a) (a).begin(), (a).end()
using ll = long long;
const int N = 4000 + 24;
const int dx[] = {1, -1, 0, 0};
const int dy[] = {0, 0, 1, -1};
int n, m; char a[N][N]; bool vis[N][N];
int cnt_visit;
bool inside(int i, int j) {
return (i >= 1 && i <= n && j >= 1 && j <= m);
}
void dfs(char c, int u, int v) {
a[u][v] = (a[u][v] == 'F' ? 'R' : 'F');
cnt_visit++; vis[u][v] = 1;
ForUp (_, 0, 3) {
int i = u + dx[_], j = v + dy[_];
if (!vis[i][j] && inside(i, j) && a[i][j] == c) {
dfs(c, i, j);
}
}
}
void solve() {
cin >> n >> m;
int cnt_all = 0;
ForUp (i, 1, n) ForUp (j, 1, m) {
cin >> a[i][j];
cnt_all += (a[i][j] != '.');
}
int res = 0;
while (true) {
ForUp (i, 1, n) ForUp (j, 1, m) vis[i][j] = 0;
cnt_visit = 0; dfs(a[1][1], 1, 1);
res++;
if (cnt_visit == cnt_all) break;
}
cout << res << '\n';
}
signed main() {
cin.tie(0) -> sync_with_stdio(0);
int T = 1; // cin >> T;
while (T--) {
solve();
}
}
