#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#ifdef _WIN32
#define getchar_unlocked _getchar_nolock
#endif
#define int long long
#define mp make_pair
#define mt make_tuple
#define pb push_back
#define ppb pop_back
#define eb emplace_back
#define g0(a) get<0>(a)
#define g1(a) get<1>(a)
#define g2(a) get<2>(a)
#define g3(a) get<3>(a)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef double db;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef tuple<int, int, int> iii;
typedef tuple<int, int, int, int> iiii;
typedef tree<ii, null_type, less<ii>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
int H, W, ans, dr[] = {-1, 0, 0, 1}, dc[] = {0, -1, 1, 0};
char curr, F[4005][4005];
queue<ii> Q;
main() {
ios::sync_with_stdio(0);
cin.tie(0);
cin >> H >> W;
for (int i = 1; i <= H; i++)
for (int j = 1; j <= W; j++) cin >> F[i][j];
while (1) {
bool f = 0, s = 0;
ans++;
for (int i = 1; i <= H; i++)
for (int j = 1; j <= W; j++)
if (F[i][j] == 'F') f = 1;
else if (F[i][j] == 'R') s = 1;
if (!f || !s) break;
curr = F[1][1];
F[1][1] = (curr == 'F' ? 'R' : 'F');
Q.emplace(1, 1);
while (!Q.empty()) {
auto [r, c] = Q.front();
Q.pop();
for (int k = 0; k < 4; k++)
if (1 <= r + dr[k] && r + dr[k] <= H && 1 <= c + dc[k] && c + dc[k] <= W && F[r + dr[k]][c + dc[k]] == curr) {
F[r + dr[k]][c + dc[k]] = (curr == 'F' ? 'R' : 'F');
Q.emplace(r + dr[k], c + dc[k]);
}
}
}
cout << ans << '\n';
}
