import java.util.Scanner;

public class Main {
    public static void main(String[]args){
        Scanner sc = new Scanner(System.in);
        String S = sc.nextLine();
        int ans = 0;

        if(S.equals("RRR")){
            ans =3;
        }else if(S.indexOf("R") == -1){
            ans = 0;
        }else{
            if(S.indexOf("RR") == -1){
                ans = 1;
            }else{
                ans = 2;
            }
        }
        System.out.println(ans);
    }
}

/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