import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {


        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        if(s.equals("RRR")) {
            System.out.println(3);
        } else if (s.equals("RRS") || s.equals("SRR")) {
            System.out.println(2);
        } else if(s.equals("SSS")){
            System.out.println(0);
        } else {
            System.out.println(1);
        }

    }

} import java.util.*; util.* java public class Main {
    public static void main(String[] args) throws Exception {


        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        if(s.equals("RRR")) {
            System.out.println(3);
        } else if (s.equals("RRS") || s.equals("SRR")) {
            System.out.println(2);
        } else if(s.equals("SSS")){
            System.out.println(0);
        } else {
            System.out.println(1);
        }

    }

} Main public static void main(String[] args) throws Exception {


        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        if(s.equals("RRR")) {
            System.out.println(3);
        } else if (s.equals("RRS") || s.equals("SRR")) {
            System.out.println(2);
        } else if(s.equals("SSS")){
            System.out.println(0);
        } else {
            System.out.println(1);
        }

    } main {


        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        if(s.equals("RRR")) {
            System.out.println(3);
        } else if (s.equals("RRS") || s.equals("SRR")) {
            System.out.println(2);
        } else if(s.equals("SSS")){
            System.out.println(0);
        } else {
            System.out.println(1);
        }

    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String s = sc.next(); s sc.next() sc.next sc if(s.equals("RRR")) {
            System.out.println(3);
        } else if (s.equals("RRS") || s.equals("SRR")) {
            System.out.println(2);
        } else if(s.equals("SSS")){
            System.out.println(0);
        } else {
            System.out.println(1);
        } s.equals("RRR") s.equals s "RRR" {
            System.out.println(3);
        } System.out.println(3) System.out.println System.out System System.out 3 if (s.equals("RRS") || s.equals("SRR")) {
            System.out.println(2);
        } else if(s.equals("SSS")){
            System.out.println(0);
        } else {
            System.out.println(1);
        } s.equals("RRS") || s.equals("SRR") s.equals("RRS") s.equals s "RRS" s.equals("SRR") s.equals s "SRR" {
            System.out.println(2);
        } System.out.println(2) System.out.println System.out System System.out 2 if(s.equals("SSS")){
            System.out.println(0);
        } else {
            System.out.println(1);
        } s.equals("SSS") s.equals s "SSS" {
            System.out.println(0);
        } System.out.println(0) System.out.println System.out System System.out 0 {
            System.out.println(1);
        } System.out.println(1) System.out.println System.out System System.out 1 String[] args args public class Main {
    public static void main(String[] args) throws Exception {


        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        if(s.equals("RRR")) {
            System.out.println(3);
        } else if (s.equals("RRS") || s.equals("SRR")) {
            System.out.println(2);
        } else if(s.equals("SSS")){
            System.out.println(0);
        } else {
            System.out.println(1);
        }

    }

} public class Main {
    public static void main(String[] args) throws Exception {


        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        if(s.equals("RRR")) {
            System.out.println(3);
        } else if (s.equals("RRS") || s.equals("SRR")) {
            System.out.println(2);
        } else if(s.equals("SSS")){
            System.out.println(0);
        } else {
            System.out.println(1);
        }

    }

} Main
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {


        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        if(s.equals("RRR")) {
            System.out.println(3);
        } else if (s.equals("RRS") || s.equals("SRR")) {
            System.out.println(2);
        } else if(s.equals("SSS")){
            System.out.println(0);
        } else {
            System.out.println(1);
        }

    }

}