#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define sz size()
#define ff first
#define ss second
#define pb push_back
#define pii pair <int, int>
#define dur exit(0)
#define dur1 return(0)
const int N = 4e3 + 5;
char a[N][N];
int n, m, vis[N][N];
queue <pii> q, q1;
int aa[] = {1, 0, -1, 0};
int bb[] = {0, 1, 0, -1};
void solve (char z) {
while (!q.empty()) {
int x = q.front().ff, y = q.front().ss;
q.pop();
if (vis[x][y]) continue;
vis[x][y] = 1;
for (int i = 0; i < 4; ++i) {
int new_x = aa[i] + x, new_y = bb[i] + y;
if (new_x < 1 or new_x > n or new_y > m or new_y < 1) continue;
if (vis[new_x][new_y] or a[new_x][new_y] == '.') continue;
if (a[new_x][new_y] != z) {
q1.push({new_x, new_y});
}
else if (a[new_x][new_y] == z) {
q.push({new_x, new_y});
}
}
}
}
int main () {
// freopen ("input.txt", "r", stdin);
ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin >> n >> m;
int sana = 0;
for (int i = 1; i <= n; ++i) {
for (int j = 1; j <= m; ++j) {
cin >> a[i][j];
if (a[i][j] != '.') sana++;
}
}
int cur = a[1][1];
q.push({1, 1});
for (int idx = 1; ; ++idx) {
solve (cur);
if (cur == 'F') cur = 'R';
else cur = 'F';
while (!q1.empty()) {
q.push(q1.front());
q1.pop();
}
if (q.empty()) return cout << idx, 0;
}
// cout << ayyr << " " << sana;
}
/*
TFFFT.....
T..F......
T..F......
T..F......
T..FFF....
TTTTTTTTTT
*/
