/*
//\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\\
\\ //
// 271828___182845__904523__53602__ \\
\\ 87___47____13______52____66__24_ //
// 97___75____72______47____09___36 \\
\\ 999595_____74______96____69___67 //
// 62___77____24______07____66__30_ \\
\\ 35___35____47______59____45713__ //
// \\
\\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\//
*/
#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <cmath>
#include <climits>
#include <algorithm>
#include <random>
#include <queue>
#include <deque>
#include <iomanip>
#include <string>
#include <tuple>
#include <bitset>
#include <chrono>
#include <ctime>
#include <fstream>
#include <stack>
#include <cstdio>
#include <functional>
using namespace std;
using LL = long long;
const int N = 1e5 + 5;
const LL mod = 1e9 + 7, inf = 1e18;
vector<int> dx = { 1, 0, -1, 0, 1, -1, 1, -1 };
vector<int> dy = { 0, -1, 0, 1, -1, 1, 1, -1 };
void solve() {
int n, m; cin >> n >> m;
vector<string> v(n);
for(int i = 0; i < n; ++i){
cin >> v[i];
}
vector<vector<int>> vis(n, vector<int> (m));
int a = 0, b = 0;
for(int i =0 ; i < n; ++i){
for(int j =0 ; j < m; ++j){
if(vis[i][j] || v[i][j] == '.') {
continue;
}
if(v[i][j] == 'R') ++a;
else ++b;
queue<pair<int, int>> q;
q.push({i, j});
vis[i][j] = 1;
while(q.size()){
int ii = q.front().first, jj = q.front().second;
q.pop();
for(int k = 0; k < 8; ++k){
int to_i = ii + dx[k], to_j = jj + dy[k];
if(to_i < 0 || to_j < 0 || to_i == n || to_j == m){
continue;
}
if(v[to_i][to_j] == '.'){
if(v[i][j] == 'R' && (vis[to_i][to_j] & 1) == 0){
vis[to_i][to_j] |= 1;
q.push({to_i, to_j});
}
else if(v[i][j] == 'F' && (vis[to_i][to_j] & 2) == 0){
vis[to_i][to_j] |= 2;
q.push({to_i, to_j});
}
}
else if(v[to_i][to_j] == v[i][j] && !vis[to_i][to_j]){
vis[to_i][to_j] = 1;
q.push({to_i, to_j});
}
}
}
}
}
cout << min(a, b) + 1 << "\n";
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
// int t; cin >> t; while (t--)
solve();
}
