#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; ++i)
using ll = long long;
using namespace std;
const int INF = 1e9;

int main() {
    int H, W;
    cin >> H >> W;

    ll ans = 0;
    rep(i, H) {
        string s;
        cin >> s;

        rep(j, s.size()) {
            if (s[j] != 'R')
                ++ans;
        }
    }

    cout << ans << endl;

    return 0;
}