import java.util.Scanner;
public class Main{
    public static void main(String args[]){
        Scanner scan = new Scanner(System.in);
        String  x = scan.next();
        String a,b,c ;
        a = x.substring(0,1);
        b = x.substring(1,2);
        c = x.substring(2,3);
        if(a.equals("R") && b.equals("R") && c.equals("R")){
            System.out.println("3");
        }else if(a.equals("R") && b.equals("R") && c.equals("S")){
            System.out.println("2");
        }else if(a.equals("S") && b.equals("R") && c.equals("R")){
            System.out.println("2");
        }else if(a.equals("R") && b.equals("S") && c.equals("S")){
            System.out.println("1");
        }else if(a.equals("S") && b.equals("R") && c.equals("S")){
            System.out.println("1");
        }else if(a.equals("S") && b.equals("S") && c.equals("R")){
            System.out.println("1");
        }else if(a.equals("R") && b.equals("S") && c.equals("R")){
            System.out.println("1");
        }else if(a.equals("S") && b.equals("S") && c.equals("S")){
            System.out.println("0");

        }else{

        }

    }
}
/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