#include <iostream>
#include <vector>
#include <queue>
using namespace std;
vector<vector<char>>grid;
vector<vector<bool>>visitado;
vector<vector<bool>>vact;
bool bfs(int n, int m, char tipo) {
bool corte=false;
queue<pair<int,int>>colaBFS;
vact.clear();
vact.assign(n, vector<bool>(m, 0));
colaBFS.push(make_pair(0,0));
visitado[0][0]=true;
vact[0][0]=true;
while(!colaBFS.empty()) {
int i=colaBFS.front().first;
int j=colaBFS.front().second;
colaBFS.pop();
if (i+1<n){
if (!visitado[i+1][j]){
if (grid[i+1][j]!='.' and grid[i+1][j]!=tipo) corte=true;
else if (grid[i+1][j]==tipo){
visitado[i+1][j]=true;
vact[i+1][j]=true;
colaBFS.push(make_pair(i+1, j));
}
}else if (!vact[i+1][j]){
vact[i+1][j]=true;
colaBFS.push(make_pair(i+1, j));
}
}if (i-1>=0){
if (!visitado[i-1][j]){
if (grid[i-1][j]!='.' and grid[i-1][j]!=tipo) corte=true;
else if (grid[i-1][j]==tipo){
visitado[i-1][j]=true;
vact[i-1][j]=true;
colaBFS.push(make_pair(i-1, j));
}
}else if (!vact[i-1][j]){
vact[i-1][j]=true;
colaBFS.push(make_pair(i-1, j));
}
}if (j+1<m){
if (!visitado[i][j+1]){
if (grid[i][j+1]!='.' and grid[i][j+1]!=tipo) corte=true;
else if (grid[i][j+1]==tipo){
visitado[i][j+1]=true;
vact[i][j+1]=true;
colaBFS.push(make_pair(i, j+1));
}
}else if (!vact[i][j+1]){
vact[i][j+1]=true;
colaBFS.push(make_pair(i, j+1));
}
}if (j-1>=0){
if (!visitado[i][j-1]){
if (grid[i][j-1]!='.' and grid[i][j-1]!=tipo) corte=true;
else if (grid[i][j-1]==tipo){
visitado[i][j-1]=true;
vact[i][j-1]=true;
colaBFS.push(make_pair(i, j-1));
}
}else if (!vact[i][j-1]){
vact[i][j-1]=true;
colaBFS.push(make_pair(i, j-1));
}
}
}return corte;
}
int main(){
int n, m;
cin>>n>>m;
grid.resize(n, vector<char>(m));
visitado.resize(n, vector<bool>(m, false));
for (int i=0; i<n; i++){
for (int j=0; j<m; j++) cin>>grid[i][j];
}int animals=0;
char tipo=grid[0][0];
while (true){
animals++;
if (bfs(n, m, tipo)==false) break;
if (tipo=='F') tipo='R';
else tipo='F';
}cout<<animals<<endl;
return 0;
}
