
import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		Scanner input =new Scanner(System.in);
		String s=input.next();
		if(s.charAt(0)=='R' && s.charAt(1)=='R' &&s.charAt(2)=='S')
		{
			System.out.println(2);
		}
		
		else if(s.charAt(1)=='R' && s.charAt(2)=='R' &&s.charAt(0)=='S')
		{
			System.out.println(2);
		}
		else if(s.charAt(0)=='R' &&s.charAt(1)=='S' && s.charAt(2)=='R')
		{
			System.out.println(1);
		}
		else if(s.charAt(0)=='S' &&s.charAt(1)=='S' && s.charAt(2)=='R')
		{
			System.out.println(1);
		}
		else if(s.charAt(0)=='R' &&s.charAt(1)=='S' && s.charAt(2)=='S')
		{
			System.out.println(1);
		}
		else if(s.charAt(0)=='S' &&s.charAt(1)=='R' && s.charAt(2)=='S')
		{
			System.out.println(1);
		}
		else if(s.charAt(0)=='R' && s.charAt(1)=='R' && s.charAt(2)=='R')
		{
			System.out.println(3);	           
		}
		else if(s.charAt(0)=='S' && s.charAt(1)=='S' && s.charAt(2)=='S')
		{
			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