import java.util.Scanner;

public class Main {

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

	}

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

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

	}

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

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

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

	}

} public class Main {

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

	}

} Main
import java.util.Scanner;

public class Main {

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

	}

}
