import java.util.*;
class Main{
public static void main(String[]args){
  Scanner sc=new Scanner(System.in);
  String s=sc.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("SRR")){
  System.out.println(2);
  }
  if(s.equals("RSS")){
  System.out.println(1);
  }
  if(s.equals("RSR")){
  System.out.println(1);
  }
  if(s.equals("RRS")){
  System.out.println(2);
  }
  if(s.equals("RRR")){
  System.out.println(3);
  }
}
}

/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