#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
#define rc(x) return cout<<x<<endl,0
#define pb push_back
#define mkp make_pair
#define in insert
#define er erase
#define fd find
#define fr first
#define sc second
typedef long long ll;
typedef long double ld;
const ll INF=0x3f3f3f3f3f3f3f3f;
const ll llinf=(1LL<<62);
const int inf=(1<<30);
const int nmax=4e3+50;
const int mod=1e9+7;
using namespace std;
int n,m,i,j,rs,ix,jx,viz[nmax][nmax],t,di[5],dj[5];
char c[nmax][nmax],cur;
queue<pair<int,int> >q,q1;
bool ok(int x,int y)
{
if(x<1 || x>n || y<1 || y>m || viz[x][y] || c[x][y]=='.')return 0;
return 1;
}
int main()
{
//freopen("sol.in","r",stdin);
//freopen("sol.out","w",stdout);
//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
ios_base::sync_with_stdio(false);cin.tie(0);cerr.tie(0);cout.tie(0);
di[0]=-1,di[1]=1,dj[2]=-1,dj[3]=1;
cin>>n>>m;
for(i=1;i<=n;i++)for(j=1;j<=m;j++)cin>>c[i][j];
cur=c[1][1];
viz[1][1]=1;
q.push(mkp(1,1));
for(rs=1;;rs++)
{
while(!q.empty())
{
i=q.front().fr,j=q.front().sc;
q.pop();
for(t=0;t<4;t++)
{
ix=i+di[t],jx=j+dj[t];
if(!ok(ix,jx))continue;
viz[ix][jx]=1;
if(c[ix][jx]==cur)q.push(mkp(ix,jx));
else q1.push(mkp(ix,jx));
}
}
if(q1.empty())break;
q=q1;
while(!q1.empty())q1.pop();
if(cur=='F')cur='R';
else cur='F';
}
cout<<rs<<endl;
return 0;
}
