import java.math.BigInteger;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		String n = sc.next();
		if (n.equals("RRR")) {
			System.out.println(3);
		} else if (n.contentEquals("SRR") || n.contentEquals("RRS")) {
			System.out.println(2);
		} else if (n.equals("SSS")) {
			System.out.println(0);
		} else {
			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