
import java.util.*;
import java.io.*;

public class Main {
    public static void main(String[] args) throws IOException {
        Scanner sc  = new Scanner(System.in);
        PrintWriter pw = new PrintWriter(System.out);
        String input = sc.next();
        if(input.contains("RRR")) pw.println(3);
        else if(input.contains("RR"))  pw.println(2);
        else if(input.contains("R")) pw.println(1);
        else pw.println(0);
        pw.close();
    }

    static class Scanner  {
        StringTokenizer st;
        BufferedReader br;

        public Scanner(InputStream s) {
            br  = new BufferedReader(new InputStreamReader(s));
        }

        public String next() throws IOException {
            while (st ==  null ||  !st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
            return st.nextToken();
        }

        public int nextInt() throws IOException { return Integer.parseInt(next()); }
        public long nextLong() throws IOException { return Long.parseLong(next()); }
        public String nextLine() throws IOException { return br.readLine(); }
        public double nextDouble() throws IOException {
            String x = next();
            StringBuilder sb  = new StringBuilder("0");
            double res = 0, f = 1;
            boolean dec = false, neg = false;
            int start = 0;
            if(x.charAt(0) == '-') {
                neg = true;
                start++;
            }
            for(int i = start; i < x.length(); i++) {
                if(x.charAt(i) == '.') {
                    res = Long.parseLong(sb.toString());
                    sb = new StringBuilder("0");
                    dec = true;
                } else {
                    sb.append(x.charAt(i));
                    if(dec) f *= 10;
                }
            }
            res += Long.parseLong(sb.toString()) /f;
            return res * (neg ? -1 : 1);
        }
        public boolean ready() throws IOException { return br.ready(); }
    }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz