#include <bits/stdc++.h>

using namespace std;
typedef long long ll;

int main(){
    int h, w;
    cin >> h >> w;
    int ans = 0;
    string s;
    for (int i = 0; i < h; i++){
        cin >> s;
        for (char x : s)
            if (x != 'R')
                ans++;
    }
    cout << ans << endl;
}