import java.util.Scanner;

public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		String record = sc.next();
		sc.close();

		int result = 0;
		if(record.indexOf("R") > -1) {
			result = 1;
		}

		if(record.indexOf("RR") > -1) {
			result = 2;
		}

		if(record.indexOf("RRR") > -1) {
			result = 3;
		}

		System.out.println(result);

	}

}
/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