import java.util.Scanner;
class Main {
  static public void main(String[] args) {
    Scanner sc = new Scanner(System.in);
      String S = sc.next();
    switch (S) {
      case "SRR": System.out.println("2"); break;
      case "RRS": System.out.println("2"); break;
      case "RRR": System.out.println("3"); break;
      case "RSR": System.out.println("1"); break;
      case "SSS": System.out.println("0"); break;
      case "SSR": System.out.println("1"); break;
      case "SRS": System.out.println("1"); break;
      case "RSS": System.out.println("1"); break;
    }
  }
}
/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