import java.util.*;

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

		int count = 0;
		String sunny = "RSR";

		for(int i=0; i<3; i++){
			if(weather.equals(sunny)){
				count= 1;
				break;
			}else if(weather.charAt(i) == 'R'){
				count++;
			}
		}
		System.out.println(count);
	}
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String weather = sc.next();

		int count = 0;
		String sunny = "RSR";

		for(int i=0; i<3; i++){
			if(weather.equals(sunny)){
				count= 1;
				break;
			}else if(weather.charAt(i) == 'R'){
				count++;
			}
		}
		System.out.println(count);
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String weather = sc.next();

		int count = 0;
		String sunny = "RSR";

		for(int i=0; i<3; i++){
			if(weather.equals(sunny)){
				count= 1;
				break;
			}else if(weather.charAt(i) == 'R'){
				count++;
			}
		}
		System.out.println(count);
	} main {
		Scanner sc = new Scanner(System.in);
		String weather = sc.next();

		int count = 0;
		String sunny = "RSR";

		for(int i=0; i<3; i++){
			if(weather.equals(sunny)){
				count= 1;
				break;
			}else if(weather.charAt(i) == 'R'){
				count++;
			}
		}
		System.out.println(count);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String weather = sc.next(); weather sc.next() sc.next sc int count = 0; count 0 String sunny = "RSR"; sunny "RSR" for(int i=0; i<3; i++){
			if(weather.equals(sunny)){
				count= 1;
				break;
			}else if(weather.charAt(i) == 'R'){
				count++;
			}
		} int i=0; int i=0; i 0 i<3 i 3 i++ i++ i {
			if(weather.equals(sunny)){
				count= 1;
				break;
			}else if(weather.charAt(i) == 'R'){
				count++;
			}
		} {
			if(weather.equals(sunny)){
				count= 1;
				break;
			}else if(weather.charAt(i) == 'R'){
				count++;
			}
		} if(weather.equals(sunny)){
				count= 1;
				break;
			}else if(weather.charAt(i) == 'R'){
				count++;
			} weather.equals(sunny) weather.equals weather sunny {
				count= 1;
				break;
			} count= 1 count 1 break; if(weather.charAt(i) == 'R'){
				count++;
			} weather.charAt(i) == 'R' weather.charAt(i) weather.charAt weather i 'R' {
				count++;
			} count++ count System.out.println(count) System.out.println System.out System System.out count String[] args args public class Main {
    public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String weather = sc.next();

		int count = 0;
		String sunny = "RSR";

		for(int i=0; i<3; i++){
			if(weather.equals(sunny)){
				count= 1;
				break;
			}else if(weather.charAt(i) == 'R'){
				count++;
			}
		}
		System.out.println(count);
	}
} public class Main {
    public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String weather = sc.next();

		int count = 0;
		String sunny = "RSR";

		for(int i=0; i<3; i++){
			if(weather.equals(sunny)){
				count= 1;
				break;
			}else if(weather.charAt(i) == 'R'){
				count++;
			}
		}
		System.out.println(count);
	}
} Main
import java.util.*;

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

		int count = 0;
		String sunny = "RSR";

		for(int i=0; i<3; i++){
			if(weather.equals(sunny)){
				count= 1;
				break;
			}else if(weather.charAt(i) == 'R'){
				count++;
			}
		}
		System.out.println(count);
	}
}
