import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
import java.util.*;
 
public class Main
{
    static class FastReader
    {
        BufferedReader br;
        StringTokenizer st;
 
        public FastReader()
        {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }
 
        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException  e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
 
        int nextInt()
        {
            return Integer.parseInt(next());
        }
 
        long nextLong()
        {
            return Long.parseLong(next());
        }
 
        double nextDouble()
        {
            return Double.parseDouble(next());
        }
 
        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
 
        int[] readArray(int n, int size){
            int[] a = new int[size];
            for(int i = 0; i < n; i++) {
                a[i] = this.nextInt();
            }
 
            return a;
        }
 
        long[] readLongArray(int n, int size){
            long[] a = new long[size];
            for(int i = 0; i < n; i++) {
                a[i] = this.nextLong();
            }
            return a;
        }
    }
 
 
 
    public static void main(String[] args) {
        FastReader s=new FastReader();
        String input = s.next();
 
        int count = 0;
        int result = count;
        for(int i = 0; i < input.length(); i++) {
 
            if(input.charAt(i) == 'R') count++;
            else {
                count = 0;
            }
 
            result = Math.max(result,count);
        }
        System.out.println(result);
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.StringTokenizer; StringTokenizer java.util import java.util.*; util.* java public class Main
{
    static class FastReader
    {
        BufferedReader br;
        StringTokenizer st;
 
        public FastReader()
        {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }
 
        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException  e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
 
        int nextInt()
        {
            return Integer.parseInt(next());
        }
 
        long nextLong()
        {
            return Long.parseLong(next());
        }
 
        double nextDouble()
        {
            return Double.parseDouble(next());
        }
 
        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
 
        int[] readArray(int n, int size){
            int[] a = new int[size];
            for(int i = 0; i < n; i++) {
                a[i] = this.nextInt();
            }
 
            return a;
        }
 
        long[] readLongArray(int n, int size){
            long[] a = new long[size];
            for(int i = 0; i < n; i++) {
                a[i] = this.nextLong();
            }
            return a;
        }
    }
 
 
 
    public static void main(String[] args) {
        FastReader s=new FastReader();
        String input = s.next();
 
        int count = 0;
        int result = count;
        for(int i = 0; i < input.length(); i++) {
 
            if(input.charAt(i) == 'R') count++;
            else {
                count = 0;
            }
 
            result = Math.max(result,count);
        }
        System.out.println(result);
    }
} Main public static void main(String[] args) {
        FastReader s=new FastReader();
        String input = s.next();
 
        int count = 0;
        int result = count;
        for(int i = 0; i < input.length(); i++) {
 
            if(input.charAt(i) == 'R') count++;
            else {
                count = 0;
            }
 
            result = Math.max(result,count);
        }
        System.out.println(result);
    } main {
        FastReader s=new FastReader();
        String input = s.next();
 
        int count = 0;
        int result = count;
        for(int i = 0; i < input.length(); i++) {
 
            if(input.charAt(i) == 'R') count++;
            else {
                count = 0;
            }
 
            result = Math.max(result,count);
        }
        System.out.println(result);
    } FastReader s=new FastReader(); s new FastReader() String input = s.next(); input s.next() s.next s int count = 0; count 0 int result = count; result count for(int i = 0; i < input.length(); i++) {
 
            if(input.charAt(i) == 'R') count++;
            else {
                count = 0;
            }
 
            result = Math.max(result,count);
        } int i = 0; int i = 0; i 0 i < input.length() i input.length() input.length input i++ i++ i {
 
            if(input.charAt(i) == 'R') count++;
            else {
                count = 0;
            }
 
            result = Math.max(result,count);
        } {
 
            if(input.charAt(i) == 'R') count++;
            else {
                count = 0;
            }
 
            result = Math.max(result,count);
        } if(input.charAt(i) == 'R') count++;
            else {
                count = 0;
            } input.charAt(i) == 'R' input.charAt(i) input.charAt input i 'R' count++ count {
                count = 0;
            } count = 0 count 0 result = Math.max(result,count) result Math.max(result,count) Math.max Math result count System.out.println(result) System.out.println System.out System System.out result String[] args args static class FastReader
    {
        BufferedReader br;
        StringTokenizer st;
 
        public FastReader()
        {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }
 
        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException  e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
 
        int nextInt()
        {
            return Integer.parseInt(next());
        }
 
        long nextLong()
        {
            return Long.parseLong(next());
        }
 
        double nextDouble()
        {
            return Double.parseDouble(next());
        }
 
        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
 
        int[] readArray(int n, int size){
            int[] a = new int[size];
            for(int i = 0; i < n; i++) {
                a[i] = this.nextInt();
            }
 
            return a;
        }
 
        long[] readLongArray(int n, int size){
            long[] a = new long[size];
            for(int i = 0; i < n; i++) {
                a[i] = this.nextLong();
            }
            return a;
        }
    } FastReader BufferedReader br; br StringTokenizer st; st public FastReader()
        {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        } FastReader {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        } br = new BufferedReader(new
                    InputStreamReader(System.in)) br new BufferedReader(new
                    InputStreamReader(System.in)) String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException  e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        } next {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException  e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        } while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException  e)
                {
                    e.printStackTrace();
                }
            } st == null || !st.hasMoreElements() st == null st null !st.hasMoreElements() st.hasMoreElements() st.hasMoreElements st {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException  e)
                {
                    e.printStackTrace();
                }
            } try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException  e)
                {
                    e.printStackTrace();
                } catch (IOException  e)
                {
                    e.printStackTrace();
                } IOException  e {
                    e.printStackTrace();
                } e.printStackTrace() e.printStackTrace e {
                    st = new StringTokenizer(br.readLine());
                } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st int nextInt()
        {
            return Integer.parseInt(next());
        } nextInt {
            return Integer.parseInt(next());
        } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nextLong()
        {
            return Long.parseLong(next());
        } nextLong {
            return Long.parseLong(next());
        } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next double nextDouble()
        {
            return Double.parseDouble(next());
        } nextDouble {
            return Double.parseDouble(next());
        } return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        } nextLine {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        } String str = ""; str "" try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            } catch (IOException e)
            {
                e.printStackTrace();
            } IOException e {
                e.printStackTrace();
            } e.printStackTrace() e.printStackTrace e {
                str = br.readLine();
            } str = br.readLine() str br.readLine() br.readLine br return str; str int[] readArray(int n, int size){
            int[] a = new int[size];
            for(int i = 0; i < n; i++) {
                a[i] = this.nextInt();
            }
 
            return a;
        } readArray {
            int[] a = new int[size];
            for(int i = 0; i < n; i++) {
                a[i] = this.nextInt();
            }
 
            return a;
        } int[] a = new int[size]; a new int[size] size for(int i = 0; i < n; i++) {
                a[i] = this.nextInt();
            } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
                a[i] = this.nextInt();
            } {
                a[i] = this.nextInt();
            } a[i] = this.nextInt() a[i] a i this.nextInt() this.nextInt this return a; a int n n int size size long[] readLongArray(int n, int size){
            long[] a = new long[size];
            for(int i = 0; i < n; i++) {
                a[i] = this.nextLong();
            }
            return a;
        } readLongArray {
            long[] a = new long[size];
            for(int i = 0; i < n; i++) {
                a[i] = this.nextLong();
            }
            return a;
        } long[] a = new long[size]; a new long[size] size for(int i = 0; i < n; i++) {
                a[i] = this.nextLong();
            } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
                a[i] = this.nextLong();
            } {
                a[i] = this.nextLong();
            } a[i] = this.nextLong() a[i] a i this.nextLong() this.nextLong this return a; a int n n int size size public class Main
{
    static class FastReader
    {
        BufferedReader br;
        StringTokenizer st;
 
        public FastReader()
        {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }
 
        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException  e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
 
        int nextInt()
        {
            return Integer.parseInt(next());
        }
 
        long nextLong()
        {
            return Long.parseLong(next());
        }
 
        double nextDouble()
        {
            return Double.parseDouble(next());
        }
 
        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
 
        int[] readArray(int n, int size){
            int[] a = new int[size];
            for(int i = 0; i < n; i++) {
                a[i] = this.nextInt();
            }
 
            return a;
        }
 
        long[] readLongArray(int n, int size){
            long[] a = new long[size];
            for(int i = 0; i < n; i++) {
                a[i] = this.nextLong();
            }
            return a;
        }
    }
 
 
 
    public static void main(String[] args) {
        FastReader s=new FastReader();
        String input = s.next();
 
        int count = 0;
        int result = count;
        for(int i = 0; i < input.length(); i++) {
 
            if(input.charAt(i) == 'R') count++;
            else {
                count = 0;
            }
 
            result = Math.max(result,count);
        }
        System.out.println(result);
    }
} public class Main
{
    static class FastReader
    {
        BufferedReader br;
        StringTokenizer st;
 
        public FastReader()
        {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }
 
        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException  e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
 
        int nextInt()
        {
            return Integer.parseInt(next());
        }
 
        long nextLong()
        {
            return Long.parseLong(next());
        }
 
        double nextDouble()
        {
            return Double.parseDouble(next());
        }
 
        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
 
        int[] readArray(int n, int size){
            int[] a = new int[size];
            for(int i = 0; i < n; i++) {
                a[i] = this.nextInt();
            }
 
            return a;
        }
 
        long[] readLongArray(int n, int size){
            long[] a = new long[size];
            for(int i = 0; i < n; i++) {
                a[i] = this.nextLong();
            }
            return a;
        }
    }
 
 
 
    public static void main(String[] args) {
        FastReader s=new FastReader();
        String input = s.next();
 
        int count = 0;
        int result = count;
        for(int i = 0; i < input.length(); i++) {
 
            if(input.charAt(i) == 'R') count++;
            else {
                count = 0;
            }
 
            result = Math.max(result,count);
        }
        System.out.println(result);
    }
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
import java.util.*;
 
public class Main
{
    static class FastReader
    {
        BufferedReader br;
        StringTokenizer st;
 
        public FastReader()
        {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }
 
        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException  e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
 
        int nextInt()
        {
            return Integer.parseInt(next());
        }
 
        long nextLong()
        {
            return Long.parseLong(next());
        }
 
        double nextDouble()
        {
            return Double.parseDouble(next());
        }
 
        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
 
        int[] readArray(int n, int size){
            int[] a = new int[size];
            for(int i = 0; i < n; i++) {
                a[i] = this.nextInt();
            }
 
            return a;
        }
 
        long[] readLongArray(int n, int size){
            long[] a = new long[size];
            for(int i = 0; i < n; i++) {
                a[i] = this.nextLong();
            }
            return a;
        }
    }
 
 
 
    public static void main(String[] args) {
        FastReader s=new FastReader();
        String input = s.next();
 
        int count = 0;
        int result = count;
        for(int i = 0; i < input.length(); i++) {
 
            if(input.charAt(i) == 'R') count++;
            else {
                count = 0;
            }
 
            result = Math.max(result,count);
        }
        System.out.println(result);
    }
}