import java.util.Scanner;
public class Main{
 public static void main(String[] args) {
   Scanner kbd =new Scanner(System.in);
   String s=kbd.next();
   int cou=0;
   if(s.contains("RRR")){
    System.out.println(3);
 }else if(s.contains("RR")){
   System.out.println(2);
 }else if(s.contains("R")){
   System.out.println(1);
}else{
  System.out.println(0);
}
}}

/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