import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		String str = sc.next();
      	if(str.contains("RRR")){System.out.println(""+3);}
      	else if(str.contains("RR")){System.out.println(""+2);}
      	else if(str.contains("R")){System.out.println(""+1);}
      	else{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