import java.io.*;

public class Main {

    public static void main(String[] args) throws IOException {
        PrintWriter prnt = new PrintWriter(System.out);
        BufferedReader read = new BufferedReader(new InputStreamReader(System.in));

        String s = read.readLine();
        int res = 0;
        if (s.charAt(0) == 'R' && s.charAt(1) == 'R' && s.charAt(2) == 'R') {
            res = 3;
        } else if (s.charAt(0) == 'R' && s.charAt(1) == 'R') {
            res = 2;
        } else if (s.charAt(1) == 'R' && s.charAt(2) == 'R') {
            res = 2;
        } else if (s.charAt(0) == 'S' && s.charAt(1) == 'S' && s.charAt(2) == 'S') {
            res = 0;
        } else {
            res = 1;
        }

        prnt.println(res);
        prnt.close();
    }
}
/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