#include<bits/stdc++.h>
using namespace std;
const int nx = 4e3+5;
int n,m,res=0;
char mat[nx][nx];
queue<pair<int,int>> all, cur;
vector<pair<int,int>> dir = { {1,0}, {-1,0}, {0,1}, {0,-1} };
void bfs(int x, int y)
{
char base = mat[x][y];
if(base == '.') return;
queue<pair<int,int>> q;
q.push({x,y});
mat[x][y] = '.';
while(!q.empty())
{
auto [r,c] = q.front();
q.pop();
for(auto [rr,cc] : dir)
{
int dr = r+rr;
int dc = c+cc;
if(mat[dr][dc] == base)
{
mat[dr][dc] = '.';
q.push({dr,dc});
}
else if(mat[dr][dc] == (base == 'F' ? 'R' : 'F')) all.push({dr,dc});
}
}
}
int main()
{
ios::sync_with_stdio(false); cin.tie(0);
cin>>n>>m;
for(int i = 1; i <= n; i++) for(int j = 1; j <= m; j++) cin>>mat[i][j];
all.push({1,1});
while(!all.empty())
{
cur = all;
if(cur.empty()) break;
while(!all.empty()) all.pop();
while(!cur.empty())
{
auto [r,c] = cur.front();
cur.pop();
bfs(r,c);
}
res++;
}
cout<<res;
}
