#include <iostream>
#include <vector>
#include <algorithm>
#include <cassert>
using ll = long long;
#define debug(x) #x << " = " << x << '\n'
const int NMAX = 4000;
const int dx[4] = {-1, 0, +1, 0};
const int dy[4] = {0, -1, 0, +1};
char a[NMAX + 2][NMAX + 2];
bool vis[NMAX + 2][NMAX + 2];
void dfs(int x, int y) {
vis[x][y] = true;
for (int k = 0; k < 4; k++) {
int xx = x + dx[k];
int yy = y + dy[k];
if (!vis[xx][yy] && a[xx][yy] == a[x][y]) {
dfs(xx, yy);
}
}
}
int main() {
#ifdef LOCAL
freopen("input.txt", "r", stdin);
#endif
std::ios_base::sync_with_stdio(false);
std::cin.tie(0);
int n, m;
std::cin >> n >> m;
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
std::cin >> a[i][j];
}
}
int pasite = 0;
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
if (a[i][j] != '.') {
pasite++;
}
}
}
int answer = 0;
while (true) {
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
vis[i][j] = false;
}
}
char c = a[1][1];
dfs(1, 1);
answer++;
int cnt = 0;
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
if (vis[i][j]) {
cnt++;
if (c == 'F') {
a[i][j] = 'R';
} else {
a[i][j] = 'F';
}
}
}
}
if (cnt == pasite) {
break;
}
}
std::cout << answer;
return 0;
}
