import java.util.Scanner;

public class Main {

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    System.out.println(solve(sc.next()));
  }
  static int solve(String s){
    if(s.contains("RRR")){
      return 3;
    } else if(s.contains("RR")){
      return 2;
    } else if(s.contains("R")){
      return 1;
    } else {
      return 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