  import java.util.Scanner;

        public class Main {
        	 public static void main(String args[]){
        	Scanner scanner = new Scanner(System.in);

        	String n=scanner.next();
        	int t=0;
               for(int i=0;i<3;i++){
            char str=n.charAt(i);
    		if(str=='R'){
                t=1;
            }}

        	for(int j=0;j<2;j++) {
          	char str1=n.charAt(j);
              char str2=n.charAt(j+1);

              if(str1==str2 && str1=='R'){
              t=t+1;
             }
        	}
        	System.out.println(t);
        	 }
        }
/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