import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		int count =0;

		if((s.charAt(0)=='R' && s.charAt(1)=='R'&& s.charAt(2)=='R')){
			System.out.println(3);
		}
		else if((s.charAt(0)=='R' && s.charAt(1)=='R') || (s.charAt(1)=='R' && s.charAt(2)=='R')) {
			System.out.println(2);
		}

		else if((s.charAt(0)=='R') || (s.charAt(1)=='R') || (s.charAt(2)=='R')){
			System.out.println(1);
		}
		else{
			System.out.println(0);
		}

	}

} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		int count =0;

		if((s.charAt(0)=='R' && s.charAt(1)=='R'&& s.charAt(2)=='R')){
			System.out.println(3);
		}
		else if((s.charAt(0)=='R' && s.charAt(1)=='R') || (s.charAt(1)=='R' && s.charAt(2)=='R')) {
			System.out.println(2);
		}

		else if((s.charAt(0)=='R') || (s.charAt(1)=='R') || (s.charAt(2)=='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();
		int count =0;

		if((s.charAt(0)=='R' && s.charAt(1)=='R'&& s.charAt(2)=='R')){
			System.out.println(3);
		}
		else if((s.charAt(0)=='R' && s.charAt(1)=='R') || (s.charAt(1)=='R' && s.charAt(2)=='R')) {
			System.out.println(2);
		}

		else if((s.charAt(0)=='R') || (s.charAt(1)=='R') || (s.charAt(2)=='R')){
			System.out.println(1);
		}
		else{
			System.out.println(0);
		}

	} main {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		int count =0;

		if((s.charAt(0)=='R' && s.charAt(1)=='R'&& s.charAt(2)=='R')){
			System.out.println(3);
		}
		else if((s.charAt(0)=='R' && s.charAt(1)=='R') || (s.charAt(1)=='R' && s.charAt(2)=='R')) {
			System.out.println(2);
		}

		else if((s.charAt(0)=='R') || (s.charAt(1)=='R') || (s.charAt(2)=='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 int count =0; count 0 if((s.charAt(0)=='R' && s.charAt(1)=='R'&& s.charAt(2)=='R')){
			System.out.println(3);
		}
		else if((s.charAt(0)=='R' && s.charAt(1)=='R') || (s.charAt(1)=='R' && s.charAt(2)=='R')) {
			System.out.println(2);
		}

		else if((s.charAt(0)=='R') || (s.charAt(1)=='R') || (s.charAt(2)=='R')){
			System.out.println(1);
		}
		else{
			System.out.println(0);
		} (s.charAt(0)=='R' && s.charAt(1)=='R'&& s.charAt(2)=='R') s.charAt(0)=='R' && s.charAt(1)=='R'&& s.charAt(2)=='R' s.charAt(0)=='R' s.charAt(0) s.charAt s 0 'R' s.charAt(1)=='R' s.charAt(1) s.charAt s 1 'R' s.charAt(2)=='R' s.charAt(2) s.charAt s 2 'R' {
			System.out.println(3);
		} System.out.println(3) System.out.println System.out System System.out 3 if((s.charAt(0)=='R' && s.charAt(1)=='R') || (s.charAt(1)=='R' && s.charAt(2)=='R')) {
			System.out.println(2);
		}

		else if((s.charAt(0)=='R') || (s.charAt(1)=='R') || (s.charAt(2)=='R')){
			System.out.println(1);
		}
		else{
			System.out.println(0);
		} (s.charAt(0)=='R' && s.charAt(1)=='R') || (s.charAt(1)=='R' && s.charAt(2)=='R') (s.charAt(0)=='R' && s.charAt(1)=='R') s.charAt(0)=='R' s.charAt(0) s.charAt s 0 'R' s.charAt(1)=='R' s.charAt(1) s.charAt s 1 'R' (s.charAt(1)=='R' && s.charAt(2)=='R') s.charAt(1)=='R' s.charAt(1) s.charAt s 1 'R' s.charAt(2)=='R' s.charAt(2) s.charAt s 2 'R' {
			System.out.println(2);
		} System.out.println(2) System.out.println System.out System System.out 2 if((s.charAt(0)=='R') || (s.charAt(1)=='R') || (s.charAt(2)=='R')){
			System.out.println(1);
		}
		else{
			System.out.println(0);
		} (s.charAt(0)=='R') || (s.charAt(1)=='R') || (s.charAt(2)=='R') (s.charAt(0)=='R') || (s.charAt(1)=='R') || (s.charAt(2)=='R') (s.charAt(0)=='R') s.charAt(0) s.charAt s 0 'R' (s.charAt(1)=='R') s.charAt(1) s.charAt s 1 'R' (s.charAt(2)=='R') s.charAt(2) s.charAt s 2 'R' {
			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) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		int count =0;

		if((s.charAt(0)=='R' && s.charAt(1)=='R'&& s.charAt(2)=='R')){
			System.out.println(3);
		}
		else if((s.charAt(0)=='R' && s.charAt(1)=='R') || (s.charAt(1)=='R' && s.charAt(2)=='R')) {
			System.out.println(2);
		}

		else if((s.charAt(0)=='R') || (s.charAt(1)=='R') || (s.charAt(2)=='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();
		int count =0;

		if((s.charAt(0)=='R' && s.charAt(1)=='R'&& s.charAt(2)=='R')){
			System.out.println(3);
		}
		else if((s.charAt(0)=='R' && s.charAt(1)=='R') || (s.charAt(1)=='R' && s.charAt(2)=='R')) {
			System.out.println(2);
		}

		else if((s.charAt(0)=='R') || (s.charAt(1)=='R') || (s.charAt(2)=='R')){
			System.out.println(1);
		}
		else{
			System.out.println(0);
		}

	}

} Main
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		int count =0;

		if((s.charAt(0)=='R' && s.charAt(1)=='R'&& s.charAt(2)=='R')){
			System.out.println(3);
		}
		else if((s.charAt(0)=='R' && s.charAt(1)=='R') || (s.charAt(1)=='R' && s.charAt(2)=='R')) {
			System.out.println(2);
		}

		else if((s.charAt(0)=='R') || (s.charAt(1)=='R') || (s.charAt(2)=='R')){
			System.out.println(1);
		}
		else{
			System.out.println(0);
		}

	}

}