import java.util.*;
public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
           Scanner sc=new Scanner(System.in);
           int c=0;
           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");
	}

} import java.util.*; util.* java public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
           Scanner sc=new Scanner(System.in);
           int c=0;
           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");
	}

} Main public static void main(String[] args) {
		// TODO Auto-generated method stub
           Scanner sc=new Scanner(System.in);
           int c=0;
           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");
	} main {
		// TODO Auto-generated method stub
           Scanner sc=new Scanner(System.in);
           int c=0;
           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");
	} Scanner sc=new Scanner(System.in); sc new Scanner(System.in) int c=0; c 0 String str=sc.next(); str sc.next() sc.next sc 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"); str.contains("RRR") str.contains str "RRR" System.out.println("3") System.out.println System.out System System.out "3" if(str.contains("RR"))
        	   System.out.println("2");
           else if(str.contains("R"))
        	   System.out.println("1");
           else
        	   System.out.println("0"); str.contains("RR") str.contains str "RR" System.out.println("2") System.out.println System.out System System.out "2" if(str.contains("R"))
        	   System.out.println("1");
           else
        	   System.out.println("0"); str.contains("R") str.contains str "R" System.out.println("1") System.out.println System.out System System.out "1" 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) {
		// TODO Auto-generated method stub
           Scanner sc=new Scanner(System.in);
           int c=0;
           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");
	}

} public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
           Scanner sc=new Scanner(System.in);
           int c=0;
           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");
	}

} Main
import java.util.*;
public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
           Scanner sc=new Scanner(System.in);
           int c=0;
           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");
	}

}
