#include<bits/stdc++.h>
using namespace std;
#define int long long
#define elif else if
#define ft first
#define sc second
#define pb push_back
#define pII pair<int,int>
#define fast_IO ios_base::sync_with_stdio(NULL);cin.tie(NULL);cout.tie(NULL)
const int sizen = 2e6+11;
const int sizen_s = 5e3+32;
const int oo = 1e16+11;
int visited[sizen_s][sizen_s];
int N,K;
int t=1, X;
int H,W;
int ODP = 0;
vector<int>vec[sizen];
char KAR[sizen_s][sizen_s];
void bfs()
{
queue<pII>Q[2];
int kolor = 0;
Q[0].push({1,1});
ODP ++;
while(!Q[kolor].empty())
{
int x = Q[kolor].front().ft;
int y = Q[kolor].front().sc;
char moj;
if(kolor == 0)
{
moj = KAR[1][1];
}
elif(1)
{
if(KAR[1][1] == 'F')
{
moj = 'R';
}
elif(1)
{
moj = 'F';
}
}
if(x > 1 && visited[x-1][y] == 0 && KAR[x-1][y] != '.')
{
visited[x-1][y] = 1;
if(KAR[x-1][y] == moj)
{
Q[kolor].push({x-1,y});
}
elif(1)
{
Q[(kolor^1)].push({x-1,y});
}
}
if(x < W && visited[x+1][y] == 0 && KAR[x+1][y] != '.')
{
visited[x+1][y] = 1;
if(KAR[x+1][y] == moj)
{
Q[kolor].push({x+1,y});
}
elif(1)
{
Q[(kolor^1)].push({x+1,y});
}
}
if(y > 1 && visited[x][y-1] == 0 && KAR[x][y-1] != '.')
{
visited[x][y-1] = 1;
if(KAR[x][y-1] == moj)
{
Q[kolor].push({x,y-1});
}
elif(1)
{
Q[(kolor^1)].push({x,y-1});
}
}
if(y < H && visited[x][y+1] == 0 && KAR[x][y+1] != '.')
{
visited[x][y+1] = 1;
if(KAR[x][y+1] == moj)
{
Q[kolor].push({x,y+1});
}
elif(1)
{
Q[(kolor^1)].push({x,y+1});
}
}
Q[kolor].pop();
if(Q[kolor].empty())
{
kolor^=1;
if(!Q[kolor].empty())
{
ODP++;
}
}
}
}
void solve()
{
cin >> H >> W;
for (int i = 1 ; i <= H; i++)
{
for (int j = 1 ; j <= W ; j++)
{
cin >> KAR[j][i];
}
}
bfs();
cout << ODP << "\n";
}
signed main()
{
//cin >> t;
while(t--)
{
solve();
}
}
