#include <bits/stdc++.h>
#define ll long long
using namespace std;
typedef vector<int> vi;
typedef pair<int,int> pi;
const int INF = 1e9;
const int MX = 5e5 + 23;
const int MOD = 1e9+7;
const int MAX_N = 1e6;
const int MAX_N2 = 1e5;
const int TWO_MOD_INV = 500000004;
const int M = 998244353;
void solve() {
int h,w,r=0,f=0;
cin >> h >> w;
char grid[h][w];
for(int i=0; i<h; ++i) {
string s;
cin >> s;
for(int j=0; j<w; ++j) {
grid[i][j]=s[j];
if(grid[i][j]=='R') ++r;
else if(grid[i][j]=='F') ++f;
}
}
queue<pair<int,int>>q;
q.push({0, 0});
bool visited[h][w];
memset(visited, 0, sizeof visited);
int ans=0;
if(r) ++ans;
if(f) ++ans;
visited[0][0]=1;
while(!q.empty()) {
int x=q.front().first, y=q.front().second;
q.pop();
if(grid[x][y]=='R') --r;
else --f;
if(x && !visited[x-1][y] && grid[x-1][y]==grid[x][y]) {
visited[x-1][y]=1;
q.push({x-1, y});
}
if(y && !visited[x][y-1] && grid[x][y-1]==grid[x][y]) {
visited[x][y-1]=1;
q.push({x, y-1});
}
if(x+1<h && !visited[x+1][y] && grid[x+1][y]==grid[x][y]) {
visited[x+1][y]=1;
q.push({x+1, y});
}
if(y+1<w && !visited[x][y+1] && grid[x][y+1]==grid[x][y]) {
visited[x][y+1]=1;
q.push({x, y+1});
}
}
if(grid[0][0]=='R' && r) ++ans;
else if(grid[0][0]=='F' && f) ++ans;
cout << ans << endl;
}
signed main()
{
//freopen("odometer.in","r",stdin);
//freopen("odometer.out","w",stdout);
int t=1;
while(t--) solve();
return 0;
}
