import java.util.*;
public class Main {
    public void solve() {
        Scanner scan = new Scanner(System.in);
        String S = scan.next();
        if (S.equals("SSS")) System.out.println(0);
        if (S.equals("SSR")) System.out.println(1);
        if (S.equals("SRS")) System.out.println(1);
        if (S.equals("RSS")) System.out.println(1);
        if (S.equals("RRS")) System.out.println(2);
        if (S.equals("RSR")) System.out.println(1);
        if (S.equals("SRR")) System.out.println(2);
        if (S.equals("RRR")) System.out.println(3);

    }

    public static void main(String[] args) {
        new Main().solve();
    }
}
/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