#include <bits/stdc++.h>
#define d1(x) cout << #x << " : " << x << endl << flush
#define d2(x, y) cout << #x << " : " << x << " " << #y << " : " << y << endl << flush
#define d3(x, y, z) cout << #x << " : " << x << " " << #y << " : " << y << " " << #z << " : " << z << endl << flush
#define d4(x, y, z, a) cout << #x << " : " << x << " " << #y << " : " << y << " " << #z << " : " << z << " "<< #a << " : " << a << endl << flush
#define ld long double
#define ll long long
#define pb push_back
#define arr(x) array <int, x>
#define endl '\n'
// #define int long long
using namespace std;
const int INF = 1e9 + 24 + (33 / 10); // 33 ---> 34
const int MAXN = 4e3 + 24 + (33 / 10); // 33 ---> 34
int dx[4] = {1, -1, -0, -0};
int dy[4] = {-0, -0, 1, -1};
int n, m;
vector <int> v, vec;
bool vis[MAXN][MAXN];
bool a[MAXN][MAXN];
int ans = 0;
void dfs(int x, int y){
vis[x][y] = 1;
v.pb((x - 1) * m + (y - 1));
for(int i = 0; i < 4; i++){
int nx = x + dx[i];
int ny = y + dy[i];
if(a[nx][ny] == a[x][y] && !vis[nx][ny])
dfs(nx, ny);
}
}
void solve(){
vec = v;
if(vec.empty())
return;
v.clear();
ans++;
for(auto eli : vec){
int x = eli / m + 1;
int y = eli % m + 1;
for(int i = 0; i < 4; i++){
int nx = x + dx[i];
int ny = y + dy[i];
if(!vis[nx][ny])
dfs(nx, ny);
}
}
solve();
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n >> m;
for(int i = 1; i <= n; i++){
for(int j = 1; j <= m; j++){
char eli;
cin >> eli;
if(eli == 'F')
a[i][j] = 1;
else if(eli == 'R')
a[i][j] = 0;
else
vis[i][j] = 1;
}
}
for(int i = 0; i <= n + 1; i++)
for(int j = 0; j <= m + 1; j++)
if(!i || !j || i == n + 1 || j == m + 1)
vis[i][j] = 1;
dfs(1, 1);
solve();
cout << ans << endl;
}
// Man hamooonam ke ye rooz...
