import java.lang.reflect.Array;
import java.util.*;
import java.io.*;
import java.lang.*;

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.lang.reflect.Array; Array java.lang.reflect import java.util.*; util.* java import java.io.*; io.* java import java.lang.*; lang.* 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 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 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 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){
        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.lang.reflect.Array;
import java.util.*;
import java.io.*;
import java.lang.*;

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);


    }
}
