#include<bits/stdc++.h>
using namespace std;
const int nx = 4e3+5;
int n,m,res=0,vis[nx][nx];
char mat[nx][nx];
vector<pair<int,int>> dir = { {1,0}, {-1,0}, {0,1}, {0,-1} };
int main()
{
ios::sync_with_stdio(false); cin.tie(0);
cin>>n>>m;
for(int i = 1; i <= n; i++) for(int j = 1; j <= m; j++) cin>>mat[i][j];
if(mat[1][1] == '.') return cout<<0, 0;
char last = mat[1][1];
char base = (last == 'R' ? 'F' : 'R');
res = 1;
for(int i = 1; i <= n; i++)
{
for(int j = 1; j <= m; j++)
{
if(mat[i][j] == base)
{
res=2;
break;
}
}
if(res==2) break;
}
queue<pair<int,int>> q;
q.push({1,1});
vis[1][1] = 1;
while(!q.empty())
{
auto [r,c] = q.front();
q.pop();
for(auto [rr, cc] : dir)
{
int dr = r+rr;
int dc = c+cc;
if(mat[dr][dc] == last && !vis[dr][dc])
{
vis[dr][dc] = 1;
q.push({dr,dc});
}
}
}
for(int i = 1; i <= n; i++)
{
for(int j = 1; j <= m; j++)
{
if(!vis[i][j] && mat[i][j] == last)
{
res=3;
break;
}
}
if(res==3) break;
}
cout<<res;
}
