#include <bits/stdc++.h>
using namespace std;
#define int long long
//#define endl "\n"
const int mod = (int) 1e9 + 7;
const int N=1005;
int n,m,ans,nm;
char c,tmp;
char v[N][N];
char imp[N][N];
bool vis[N][N];
bool bl;
int dx[4]={0,0,1,-1};
int dy[4]={1,-1,0,0};
bool chk(int i,int j) {
return i>=0 && j>=0 && i<n && j<m && !vis[i][j] && v[i][j]==tmp && imp[i][j]!='*';
}
void bfs(int a,int b) {
queue<pair<int,int> > q; q.push({a,b});
while (!q.empty()) {
int i=q.front().first;
int j=q.front().second;
q.pop();
vis[i][j]=true;
for (int p=0;p<4;p++) {
int ii=i+dx[p],jj=j+dy[p];
if (chk(ii,jj)) {
nm--; bl=true; bfs(ii,jj);}
}
}
}
signed main()
{
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
//freopen(".in", "r", stdin); freopen(".out", "w", stdout);
cin>>n>>m;
for (int i=0;i<n;i++) {
for (int j=0;j<m;j++) {
cin>>v[i][j];
if (v[i][j]=='.') {imp[i][j]='*';}
else {nm++;}
}
}
c=v[0][0]; tmp=v[0][0]; nm--; bfs(0,0); ans++;
while (nm>0) {
bl=false;
for (int i=0;i<n;i++) {
for (int j=0;j<m;j++) {
if (vis[i][j] && v[i][j]==c && imp[i][j]!='*') {
if (c=='R') {tmp='F';}
else {tmp='R';}
nm--; bfs(i,j);
imp[i][j]='*';
}
}
}
c=tmp;
if (bl) {ans++;}
}
cout<<ans;
}
