import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
      String S = sc.next();
      if(S.contains("RRR")){
        System.out.println("3");
      }else if(S.contains("RR")){
        System.out.println("2");
      }else if(S.contains("R")){
        System.out.println("1");
      }else{
        System.out.println("0");
      }
    }
} import java.util.*; util.* java public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
      String S = sc.next();
      if(S.contains("RRR")){
        System.out.println("3");
      }else if(S.contains("RR")){
        System.out.println("2");
      }else if(S.contains("R")){
        System.out.println("1");
      }else{
        System.out.println("0");
      }
    }
} Main public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
      String S = sc.next();
      if(S.contains("RRR")){
        System.out.println("3");
      }else if(S.contains("RR")){
        System.out.println("2");
      }else if(S.contains("R")){
        System.out.println("1");
      }else{
        System.out.println("0");
      }
    } main {
		Scanner sc = new Scanner(System.in);
      String S = sc.next();
      if(S.contains("RRR")){
        System.out.println("3");
      }else if(S.contains("RR")){
        System.out.println("2");
      }else if(S.contains("R")){
        System.out.println("1");
      }else{
        System.out.println("0");
      }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String S = sc.next(); S sc.next() sc.next sc if(S.contains("RRR")){
        System.out.println("3");
      }else if(S.contains("RR")){
        System.out.println("2");
      }else if(S.contains("R")){
        System.out.println("1");
      }else{
        System.out.println("0");
      } S.contains("RRR") S.contains S "RRR" {
        System.out.println("3");
      } System.out.println("3") System.out.println System.out System System.out "3" if(S.contains("RR")){
        System.out.println("2");
      }else if(S.contains("R")){
        System.out.println("1");
      }else{
        System.out.println("0");
      } S.contains("RR") S.contains S "RR" {
        System.out.println("2");
      } System.out.println("2") System.out.println System.out System System.out "2" if(S.contains("R")){
        System.out.println("1");
      }else{
        System.out.println("0");
      } S.contains("R") S.contains S "R" {
        System.out.println("1");
      } System.out.println("1") System.out.println System.out System System.out "1" {
        System.out.println("0");
      } System.out.println("0") System.out.println System.out System System.out "0" String[] args args public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
      String S = sc.next();
      if(S.contains("RRR")){
        System.out.println("3");
      }else if(S.contains("RR")){
        System.out.println("2");
      }else if(S.contains("R")){
        System.out.println("1");
      }else{
        System.out.println("0");
      }
    }
} public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
      String S = sc.next();
      if(S.contains("RRR")){
        System.out.println("3");
      }else if(S.contains("RR")){
        System.out.println("2");
      }else if(S.contains("R")){
        System.out.println("1");
      }else{
        System.out.println("0");
      }
    }
} Main
import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
      String S = sc.next();
      if(S.contains("RRR")){
        System.out.println("3");
      }else if(S.contains("RR")){
        System.out.println("2");
      }else if(S.contains("R")){
        System.out.println("1");
      }else{
        System.out.println("0");
      }
    }
}