import java.util.*;
import java.util.stream.Stream;
import java.time.*;
import java.time.format.*;

public class No712 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
        int m = sc.nextInt();
        int t = 0;
        for(int i = 0; i < n; i++) {
            t += sc.next().replace("R" , "").length();
        }
        System.out.println(t);
	}
}