#include<bits/stdc++.h>
using namespace std;
#define int long long
#define ff first
#define ss second
#define pb push_back
const int N=4444;
char a[N][N];
bool vis[N][N];
int xx[4]={1,-1,0,0};
int yy[4]={0,0,1,-1};
pair<int,int>par[N][N];
int lvl[N][N];
bool lvlvis[N*N];
signed main(){
int n,m;
cin>>n>>m;
for(int i=1;i<=n;i++){
for(int j=1;j<=m;j++)cin>>a[i][j];
}
queue<pair<int,int>>q,hq;
q.push({n,m});
int p=1;
while(!(q.empty() and hq.empty())){
int y,x;
if(!q.empty()){
y=q.front().ff,x=q.front().ss;
q.pop();
if(vis[y][x])continue;
}
else{
while(!hq.empty()){
y=hq.front().ff,x=hq.front().ss;
hq.pop();
if(vis[y][x]==0){
int py=par[y][x].ff,px=par[y][x].ss;
if(lvlvis[lvl[py][px]]==0)p++;
lvlvis[lvl[py][px]]=1;
break;
}
}
if(vis[y][x])continue;
}
if(y==0 or x==0)continue;
vis[y][x]=1;
lvl[y][x]=p;
char c=a[y][x];
for(int i=0;i<4;i++){
if(vis[y+yy[i]][x+xx[i]]==0){
if(a[y+yy[i]][x+xx[i]]==c){
q.push({y+yy[i],x+xx[i]});
}
else if(a[y+yy[i]][x+xx[i]]=='F' or a[y+yy[i]][x+xx[i]]=='R'){
par[y+yy[i]][x+xx[i]]={y,x};
hq.push({y+yy[i],x+xx[i]});
}
}
}
}
cout<<p;
}
