import java.util.*;
public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String L = sc.nextLine();
        
        switch(L){
            case "SSS":
                System.out.println("0");
                break;
            case "SSR":
                System.out.println("1");
                break;
            case "SRS":
                System.out.println("1");
                break;
            case "RSS":
                System.out.println("1");
                break;
            case "RRS":
                System.out.println("2");
                break;
            case "RSR":
                System.out.println("1");
                break;
            case "SRR":
                System.out.println("2");
                break;
            case "RRR":
                System.out.println("3");
                break;
        }
    }
}








/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