import java.util.*;

public class Main{
  public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String S = sc.next();
		if(S.length() == 3) {
			if(S.equals("RRR")) {
				System.out.println("3");
			}else if(S.equals("RRS") || S.equals("SRR")) {
				System.out.println("2");
			}else if(S.equals("RSR") || S.equals("SRS") || S.equals("SSR") || S.equals("RSS")) {
				System.out.println("1");
			}else {
				System.out.println("0");
			}
		}
	}
} import java.util.*; util.* java public class Main{
  public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String S = sc.next();
		if(S.length() == 3) {
			if(S.equals("RRR")) {
				System.out.println("3");
			}else if(S.equals("RRS") || S.equals("SRR")) {
				System.out.println("2");
			}else if(S.equals("RSR") || S.equals("SRS") || S.equals("SSR") || S.equals("RSS")) {
				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.length() == 3) {
			if(S.equals("RRR")) {
				System.out.println("3");
			}else if(S.equals("RRS") || S.equals("SRR")) {
				System.out.println("2");
			}else if(S.equals("RSR") || S.equals("SRS") || S.equals("SSR") || S.equals("RSS")) {
				System.out.println("1");
			}else {
				System.out.println("0");
			}
		}
	} main {
		Scanner sc = new Scanner(System.in);
		String S = sc.next();
		if(S.length() == 3) {
			if(S.equals("RRR")) {
				System.out.println("3");
			}else if(S.equals("RRS") || S.equals("SRR")) {
				System.out.println("2");
			}else if(S.equals("RSR") || S.equals("SRS") || S.equals("SSR") || S.equals("RSS")) {
				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.length() == 3) {
			if(S.equals("RRR")) {
				System.out.println("3");
			}else if(S.equals("RRS") || S.equals("SRR")) {
				System.out.println("2");
			}else if(S.equals("RSR") || S.equals("SRS") || S.equals("SSR") || S.equals("RSS")) {
				System.out.println("1");
			}else {
				System.out.println("0");
			}
		} S.length() == 3 S.length() S.length S 3 {
			if(S.equals("RRR")) {
				System.out.println("3");
			}else if(S.equals("RRS") || S.equals("SRR")) {
				System.out.println("2");
			}else if(S.equals("RSR") || S.equals("SRS") || S.equals("SSR") || S.equals("RSS")) {
				System.out.println("1");
			}else {
				System.out.println("0");
			}
		} if(S.equals("RRR")) {
				System.out.println("3");
			}else if(S.equals("RRS") || S.equals("SRR")) {
				System.out.println("2");
			}else if(S.equals("RSR") || S.equals("SRS") || S.equals("SSR") || S.equals("RSS")) {
				System.out.println("1");
			}else {
				System.out.println("0");
			} 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("RSR") || S.equals("SRS") || S.equals("SSR") || S.equals("RSS")) {
				System.out.println("1");
			}else {
				System.out.println("0");
			} 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("RSR") || S.equals("SRS") || S.equals("SSR") || S.equals("RSS")) {
				System.out.println("1");
			}else {
				System.out.println("0");
			} S.equals("RSR") || S.equals("SRS") || S.equals("SSR") || S.equals("RSS") S.equals("SSR") S.equals("RSR") || S.equals("SRS") || S.equals("SSR") || S.equals("RSS") S.equals("RSR") S.equals S "RSR" S.equals("SRS") S.equals S "SRS" S.equals("SSR") S.equals S "SSR" S.equals("RSS") S.equals S "RSS" {
				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();
		if(S.length() == 3) {
			if(S.equals("RRR")) {
				System.out.println("3");
			}else if(S.equals("RRS") || S.equals("SRR")) {
				System.out.println("2");
			}else if(S.equals("RSR") || S.equals("SRS") || S.equals("SSR") || S.equals("RSS")) {
				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.length() == 3) {
			if(S.equals("RRR")) {
				System.out.println("3");
			}else if(S.equals("RRS") || S.equals("SRR")) {
				System.out.println("2");
			}else if(S.equals("RSR") || S.equals("SRS") || S.equals("SSR") || S.equals("RSS")) {
				System.out.println("1");
			}else {
				System.out.println("0");
			}
		}
	}
} Main
import java.util.*;

public class Main{
  public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String S = sc.next();
		if(S.length() == 3) {
			if(S.equals("RRR")) {
				System.out.println("3");
			}else if(S.equals("RRS") || S.equals("SRR")) {
				System.out.println("2");
			}else if(S.equals("RSR") || S.equals("SRS") || S.equals("SSR") || S.equals("RSS")) {
				System.out.println("1");
			}else {
				System.out.println("0");
			}
		}
	}
}