import java.util.*;

public class Main{
	static public void main(String[] args){
		Scanner sc=new Scanner(System.in);
		String str=sc.next();
		char ch1=str.charAt(0),ch2=str.charAt(1),ch3=str.charAt(2);
		
		if(ch1==ch2&&ch2==ch3&&ch1=='S'){
			System.out.println(0);
			return;
		}
		if(ch1==ch2&&ch2==ch3&&ch1=='R')System.out.println(3);
		else if(ch1=='R'){
			if(ch1==ch2)System.out.println(2);
			else System.out.println(1);
		}
		else if(ch3=='R'){
			if(ch2==ch3)System.out.println(2);
			else System.out.println(1);
		}
		else System.out.println(1);
		sc.close();
		return;
	}
}
/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