#include <bits/stdc++.h>
using namespace std;
int dir_x[] = {1, -1, 0, 0};
int dir_y[] = {0, 0, 1, -1};
int main()
{
int n, m;
cin >> n >> m;
vector<vector<char>> grid(n, vector<char> (m));
for(int i = 0; i < n; i++)
{
for(int j = 0; j < m; j++)
{
cin >> grid[i][j];
}
}
queue<pair<int, int>> fox, rabbit;
vector<vector<bool>> visited(n, vector<bool> (m));
if(grid[0][0] == 'F')
{
fox.push({0, 0});
}
else
{
rabbit.push({0, 0});
}
visited[0][0] = true;
int ans = 0;
while(fox.size() || rabbit.size())
{
if(fox.size())
{
ans++;
}
while(fox.size())
{
auto src = fox.front();
fox.pop();
for(int i = 0; i < 4; i++)
{
int x = src.first + dir_x[i], y = src.second + dir_y[i];
if(x >= 0 && x < n && y >= 0 && y < m && visited[x][y] == false && grid[x][y] != '.')
{
visited[x][y] = true;
if(grid[x][y] == 'F')
{
fox.push({x, y});
}
else
{
rabbit.push({x, y});
}
}
}
}
if(rabbit.size())
{
ans++;
}
while(rabbit.size())
{
auto src = rabbit.front();
rabbit.pop();
for(int i = 0; i < 4; i++)
{
int x = src.first + dir_x[i], y = src.second + dir_y[i];
if(x >= 0 && x < n && y >= 0 && y < m && visited[x][y] == false && grid[x][y] != '.')
{
visited[x][y] = true;
if(grid[x][y] == 'F')
{
fox.push({x, y});
}
else
{
rabbit.push({x, y});
}
}
}
}
}
cout << ans << endl;
return 0;
}
