#ifdef LOCAL
#include ".debug.hpp"
#else
#define debug(...) 42
#endif
#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;
using ordered_set = tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>;
signed main() {
#ifndef VOID
cin.tie(nullptr)->sync_with_stdio(false);
#endif
int N, M; cin >> N >> M;
vector<vector<char>> A(N, vector<char> (M));
for (int i = 0; i < N; i++) for (int j = 0; j < M; j++) cin >> A[i][j];
int ans = 1;
vector<vector<bool>> vis(N, vector<bool> (M));
auto free = [&](const int &x, const int &y) -> bool {
return x >= 0 && y >= 0 && x < N && y < M && !vis[x][y];
};
const vector<int> DX = {1, -1, 0, 0}, DY = {0, 0, 1, -1};
char turn = A[0][0];
deque<array<int, 2>> dq; dq.push_back({0, 0});
if (turn == '.') {
cout << "0\n";
return 0;
}
while (!dq.empty()) {
int X, Y;
if (turn == 'R') X = dq.front()[0], Y = dq.front()[1], dq.pop_front();
else X = dq.back()[0], Y = dq.back()[1], dq.pop_back();
bool flag = false;
if (turn == 'R' && A[X][Y] == 'F') turn = 'F', ans++, dq.push_front({X, Y}), flag = true;
else if (turn == 'F' && A[X][Y] == 'R') turn = 'R', ans++, dq.push_back({X, Y}), flag = true;
if (flag) {
if (turn == 'R') X = dq.front()[0], Y = dq.front()[1], dq.pop_front();
else X = dq.back()[0], Y = dq.back()[1], dq.pop_back();
}
vis[X][Y] = true;
for (int d = 0; d < 4; d++) {
int toX = X + DX[d], toY = Y + DY[d];
if (!free(toX, toY)) continue;
if (A[toX][toY] == 'F') dq.push_back({toX, toY});
else dq.push_front({toX, toY});
}
}
cout << ans;
return 0;
}
