import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		
		String weather = sc.next();
		
		if(weather.equals("SSS")) {
			System.out.println(0);
			return;
		}
		
		if(weather.equals("RRR")) {
			System.out.println(3);
			return;
		}
		
		if(weather.equals("RRS")||weather.equals("SRR")) {
			System.out.println(2);
			return;
		}
		
		System.out.println(1);


		
	}
}
/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