import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		
		if(s.indexOf("RRR") != -1) {
			System.out.println("3");
		}else if(s.indexOf("RR") != -1){
			System.out.println("2");
		}else if(s.indexOf("R") != -1) {
			System.out.println("1");
		}else {
			System.out.println("0");
		}
	}

} import java.util.Scanner; Scanner java.util import java.util.regex.Matcher; Matcher java.util.regex import java.util.regex.Pattern; Pattern java.util.regex public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		
		if(s.indexOf("RRR") != -1) {
			System.out.println("3");
		}else if(s.indexOf("RR") != -1){
			System.out.println("2");
		}else if(s.indexOf("R") != -1) {
			System.out.println("1");
		}else {
			System.out.println("0");
		}
	}

} Main public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		
		if(s.indexOf("RRR") != -1) {
			System.out.println("3");
		}else if(s.indexOf("RR") != -1){
			System.out.println("2");
		}else if(s.indexOf("R") != -1) {
			System.out.println("1");
		}else {
			System.out.println("0");
		}
	} main {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		
		if(s.indexOf("RRR") != -1) {
			System.out.println("3");
		}else if(s.indexOf("RR") != -1){
			System.out.println("2");
		}else if(s.indexOf("R") != -1) {
			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.indexOf("RRR") != -1) {
			System.out.println("3");
		}else if(s.indexOf("RR") != -1){
			System.out.println("2");
		}else if(s.indexOf("R") != -1) {
			System.out.println("1");
		}else {
			System.out.println("0");
		} s.indexOf("RRR") != -1 s.indexOf("RRR") s.indexOf s "RRR" -1 1 {
			System.out.println("3");
		} System.out.println("3") System.out.println System.out System System.out "3" if(s.indexOf("RR") != -1){
			System.out.println("2");
		}else if(s.indexOf("R") != -1) {
			System.out.println("1");
		}else {
			System.out.println("0");
		} s.indexOf("RR") != -1 s.indexOf("RR") s.indexOf s "RR" -1 1 {
			System.out.println("2");
		} System.out.println("2") System.out.println System.out System System.out "2" if(s.indexOf("R") != -1) {
			System.out.println("1");
		}else {
			System.out.println("0");
		} s.indexOf("R") != -1 s.indexOf("R") s.indexOf s "R" -1 1 {
			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) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		
		if(s.indexOf("RRR") != -1) {
			System.out.println("3");
		}else if(s.indexOf("RR") != -1){
			System.out.println("2");
		}else if(s.indexOf("R") != -1) {
			System.out.println("1");
		}else {
			System.out.println("0");
		}
	}

} public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		
		if(s.indexOf("RRR") != -1) {
			System.out.println("3");
		}else if(s.indexOf("RR") != -1){
			System.out.println("2");
		}else if(s.indexOf("R") != -1) {
			System.out.println("1");
		}else {
			System.out.println("0");
		}
	}

} Main
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		
		if(s.indexOf("RRR") != -1) {
			System.out.println("3");
		}else if(s.indexOf("RR") != -1){
			System.out.println("2");
		}else if(s.indexOf("R") != -1) {
			System.out.println("1");
		}else {
			System.out.println("0");
		}
	}

}