using System;
using System.Text.RegularExpressions;
using System.Linq;

class Program
{
    public void Solve()
    {
        int[] NM = Console.ReadLine().Split(' ').Select(X => int.Parse(X)).ToArray();
        int fill = 0;
        for (int i = 1; i <= NM[0]; i++)
        {
            var A = Console.ReadLine();
            fill += A.Replace("R", "").Length;
        }
        Console.WriteLine(fill);
    }

    static void Main()
    {
        var solver = new Program();
        solver.Solve();
    }
}