import java.util.*;

class Main{
    static Scanner sc = new Scanner(System.in);

    public static void main(String args[]){
        String S=sc.next();
        if(S.equals("RRR")) System.out.println(3);
        else if(S.equals("RSR")||S.equals("RSS")||S.equals("SSR")||S.equals("SRS")) System.out.println(1);
      	else if(S.equals("SSS")) System.out.println(0);
        else System.out.println(2);
    }
}

/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