
import java.util.*;
import java.io.*;

public class Main {
    public static void main(String[] args) throws IOException {
        Scanner sc  = new Scanner(System.in);
        PrintWriter pw = new PrintWriter(System.out);
        String input = sc.next();
        if(input.contains("RRR")) pw.println(3);
        else if(input.contains("RR"))  pw.println(2);
        else if(input.contains("R")) pw.println(1);
        else pw.println(0);
        pw.close();
    }

    static class Scanner  {
        StringTokenizer st;
        BufferedReader br;

        public Scanner(InputStream s) {
            br  = new BufferedReader(new InputStreamReader(s));
        }

        public String next() throws IOException {
            while (st ==  null ||  !st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
            return st.nextToken();
        }

        public int nextInt() throws IOException { return Integer.parseInt(next()); }
        public long nextLong() throws IOException { return Long.parseLong(next()); }
        public String nextLine() throws IOException { return br.readLine(); }
        public double nextDouble() throws IOException {
            String x = next();
            StringBuilder sb  = new StringBuilder("0");
            double res = 0, f = 1;
            boolean dec = false, neg = false;
            int start = 0;
            if(x.charAt(0) == '-') {
                neg = true;
                start++;
            }
            for(int i = start; i < x.length(); i++) {
                if(x.charAt(i) == '.') {
                    res = Long.parseLong(sb.toString());
                    sb = new StringBuilder("0");
                    dec = true;
                } else {
                    sb.append(x.charAt(i));
                    if(dec) f *= 10;
                }
            }
            res += Long.parseLong(sb.toString()) /f;
            return res * (neg ? -1 : 1);
        }
        public boolean ready() throws IOException { return br.ready(); }
    }
} import java.util.*; util.* java import java.io.*; io.* java public class Main {
    public static void main(String[] args) throws IOException {
        Scanner sc  = new Scanner(System.in);
        PrintWriter pw = new PrintWriter(System.out);
        String input = sc.next();
        if(input.contains("RRR")) pw.println(3);
        else if(input.contains("RR"))  pw.println(2);
        else if(input.contains("R")) pw.println(1);
        else pw.println(0);
        pw.close();
    }

    static class Scanner  {
        StringTokenizer st;
        BufferedReader br;

        public Scanner(InputStream s) {
            br  = new BufferedReader(new InputStreamReader(s));
        }

        public String next() throws IOException {
            while (st ==  null ||  !st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
            return st.nextToken();
        }

        public int nextInt() throws IOException { return Integer.parseInt(next()); }
        public long nextLong() throws IOException { return Long.parseLong(next()); }
        public String nextLine() throws IOException { return br.readLine(); }
        public double nextDouble() throws IOException {
            String x = next();
            StringBuilder sb  = new StringBuilder("0");
            double res = 0, f = 1;
            boolean dec = false, neg = false;
            int start = 0;
            if(x.charAt(0) == '-') {
                neg = true;
                start++;
            }
            for(int i = start; i < x.length(); i++) {
                if(x.charAt(i) == '.') {
                    res = Long.parseLong(sb.toString());
                    sb = new StringBuilder("0");
                    dec = true;
                } else {
                    sb.append(x.charAt(i));
                    if(dec) f *= 10;
                }
            }
            res += Long.parseLong(sb.toString()) /f;
            return res * (neg ? -1 : 1);
        }
        public boolean ready() throws IOException { return br.ready(); }
    }
} Main public static void main(String[] args) throws IOException {
        Scanner sc  = new Scanner(System.in);
        PrintWriter pw = new PrintWriter(System.out);
        String input = sc.next();
        if(input.contains("RRR")) pw.println(3);
        else if(input.contains("RR"))  pw.println(2);
        else if(input.contains("R")) pw.println(1);
        else pw.println(0);
        pw.close();
    } main {
        Scanner sc  = new Scanner(System.in);
        PrintWriter pw = new PrintWriter(System.out);
        String input = sc.next();
        if(input.contains("RRR")) pw.println(3);
        else if(input.contains("RR"))  pw.println(2);
        else if(input.contains("R")) pw.println(1);
        else pw.println(0);
        pw.close();
    } Scanner sc  = new Scanner(System.in); sc new Scanner(System.in) PrintWriter pw = new PrintWriter(System.out); pw new PrintWriter(System.out) String input = sc.next(); input sc.next() sc.next sc if(input.contains("RRR")) pw.println(3);
        else if(input.contains("RR"))  pw.println(2);
        else if(input.contains("R")) pw.println(1);
        else pw.println(0); input.contains("RRR") input.contains input "RRR" pw.println(3) pw.println pw 3 if(input.contains("RR"))  pw.println(2);
        else if(input.contains("R")) pw.println(1);
        else pw.println(0); input.contains("RR") input.contains input "RR" pw.println(2) pw.println pw 2 if(input.contains("R")) pw.println(1);
        else pw.println(0); input.contains("R") input.contains input "R" pw.println(1) pw.println pw 1 pw.println(0) pw.println pw 0 pw.close() pw.close pw String[] args args static class Scanner  {
        StringTokenizer st;
        BufferedReader br;

        public Scanner(InputStream s) {
            br  = new BufferedReader(new InputStreamReader(s));
        }

        public String next() throws IOException {
            while (st ==  null ||  !st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
            return st.nextToken();
        }

        public int nextInt() throws IOException { return Integer.parseInt(next()); }
        public long nextLong() throws IOException { return Long.parseLong(next()); }
        public String nextLine() throws IOException { return br.readLine(); }
        public double nextDouble() throws IOException {
            String x = next();
            StringBuilder sb  = new StringBuilder("0");
            double res = 0, f = 1;
            boolean dec = false, neg = false;
            int start = 0;
            if(x.charAt(0) == '-') {
                neg = true;
                start++;
            }
            for(int i = start; i < x.length(); i++) {
                if(x.charAt(i) == '.') {
                    res = Long.parseLong(sb.toString());
                    sb = new StringBuilder("0");
                    dec = true;
                } else {
                    sb.append(x.charAt(i));
                    if(dec) f *= 10;
                }
            }
            res += Long.parseLong(sb.toString()) /f;
            return res * (neg ? -1 : 1);
        }
        public boolean ready() throws IOException { return br.ready(); }
    } Scanner StringTokenizer st; st BufferedReader br; br public Scanner(InputStream s) {
            br  = new BufferedReader(new InputStreamReader(s));
        } Scanner {
            br  = new BufferedReader(new InputStreamReader(s));
        } br  = new BufferedReader(new InputStreamReader(s)) br new BufferedReader(new InputStreamReader(s)) InputStream s s public String next() throws IOException {
            while (st ==  null ||  !st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
            return st.nextToken();
        } next {
            while (st ==  null ||  !st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
            return st.nextToken();
        } while (st ==  null ||  !st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            } st ==  null ||  !st.hasMoreTokens() st ==  null st null !st.hasMoreTokens() st.hasMoreTokens() st.hasMoreTokens st {
                st = new StringTokenizer(br.readLine());
            } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st public int nextInt() throws IOException { return Integer.parseInt(next()); } nextInt { return Integer.parseInt(next()); } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next public long nextLong() throws IOException { return Long.parseLong(next()); } nextLong { return Long.parseLong(next()); } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next public String nextLine() throws IOException { return br.readLine(); } nextLine { return br.readLine(); } return br.readLine(); br.readLine() br.readLine br public double nextDouble() throws IOException {
            String x = next();
            StringBuilder sb  = new StringBuilder("0");
            double res = 0, f = 1;
            boolean dec = false, neg = false;
            int start = 0;
            if(x.charAt(0) == '-') {
                neg = true;
                start++;
            }
            for(int i = start; i < x.length(); i++) {
                if(x.charAt(i) == '.') {
                    res = Long.parseLong(sb.toString());
                    sb = new StringBuilder("0");
                    dec = true;
                } else {
                    sb.append(x.charAt(i));
                    if(dec) f *= 10;
                }
            }
            res += Long.parseLong(sb.toString()) /f;
            return res * (neg ? -1 : 1);
        } nextDouble {
            String x = next();
            StringBuilder sb  = new StringBuilder("0");
            double res = 0, f = 1;
            boolean dec = false, neg = false;
            int start = 0;
            if(x.charAt(0) == '-') {
                neg = true;
                start++;
            }
            for(int i = start; i < x.length(); i++) {
                if(x.charAt(i) == '.') {
                    res = Long.parseLong(sb.toString());
                    sb = new StringBuilder("0");
                    dec = true;
                } else {
                    sb.append(x.charAt(i));
                    if(dec) f *= 10;
                }
            }
            res += Long.parseLong(sb.toString()) /f;
            return res * (neg ? -1 : 1);
        } String x = next(); x next() next StringBuilder sb  = new StringBuilder("0"); sb new StringBuilder("0") double res = 0 res 0 f = 1; f 1 boolean dec = false dec false neg = false; neg false int start = 0; start 0 if(x.charAt(0) == '-') {
                neg = true;
                start++;
            } x.charAt(0) == '-' x.charAt(0) x.charAt x 0 '-' {
                neg = true;
                start++;
            } neg = true neg true start++ start for(int i = start; i < x.length(); i++) {
                if(x.charAt(i) == '.') {
                    res = Long.parseLong(sb.toString());
                    sb = new StringBuilder("0");
                    dec = true;
                } else {
                    sb.append(x.charAt(i));
                    if(dec) f *= 10;
                }
            } int i = start; int i = start; i start i < x.length() i x.length() x.length x i++ i++ i {
                if(x.charAt(i) == '.') {
                    res = Long.parseLong(sb.toString());
                    sb = new StringBuilder("0");
                    dec = true;
                } else {
                    sb.append(x.charAt(i));
                    if(dec) f *= 10;
                }
            } {
                if(x.charAt(i) == '.') {
                    res = Long.parseLong(sb.toString());
                    sb = new StringBuilder("0");
                    dec = true;
                } else {
                    sb.append(x.charAt(i));
                    if(dec) f *= 10;
                }
            } if(x.charAt(i) == '.') {
                    res = Long.parseLong(sb.toString());
                    sb = new StringBuilder("0");
                    dec = true;
                } else {
                    sb.append(x.charAt(i));
                    if(dec) f *= 10;
                } x.charAt(i) == '.' x.charAt(i) x.charAt x i '.' {
                    res = Long.parseLong(sb.toString());
                    sb = new StringBuilder("0");
                    dec = true;
                } res = Long.parseLong(sb.toString()) res Long.parseLong(sb.toString()) Long.parseLong Long sb.toString() sb.toString sb sb = new StringBuilder("0") sb new StringBuilder("0") dec = true dec true {
                    sb.append(x.charAt(i));
                    if(dec) f *= 10;
                } sb.append(x.charAt(i)) sb.append sb x.charAt(i) x.charAt x i if(dec) f *= 10; dec f *= 10 f 10 res += Long.parseLong(sb.toString()) /f res Long.parseLong(sb.toString()) /f Long.parseLong(sb.toString()) Long.parseLong Long sb.toString() sb.toString sb f return res * (neg ? -1 : 1); res * (neg ? -1 : 1) res (neg ? -1 : 1) neg -1 1 1 public boolean ready() throws IOException { return br.ready(); } ready { return br.ready(); } return br.ready(); br.ready() br.ready br public class Main {
    public static void main(String[] args) throws IOException {
        Scanner sc  = new Scanner(System.in);
        PrintWriter pw = new PrintWriter(System.out);
        String input = sc.next();
        if(input.contains("RRR")) pw.println(3);
        else if(input.contains("RR"))  pw.println(2);
        else if(input.contains("R")) pw.println(1);
        else pw.println(0);
        pw.close();
    }

    static class Scanner  {
        StringTokenizer st;
        BufferedReader br;

        public Scanner(InputStream s) {
            br  = new BufferedReader(new InputStreamReader(s));
        }

        public String next() throws IOException {
            while (st ==  null ||  !st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
            return st.nextToken();
        }

        public int nextInt() throws IOException { return Integer.parseInt(next()); }
        public long nextLong() throws IOException { return Long.parseLong(next()); }
        public String nextLine() throws IOException { return br.readLine(); }
        public double nextDouble() throws IOException {
            String x = next();
            StringBuilder sb  = new StringBuilder("0");
            double res = 0, f = 1;
            boolean dec = false, neg = false;
            int start = 0;
            if(x.charAt(0) == '-') {
                neg = true;
                start++;
            }
            for(int i = start; i < x.length(); i++) {
                if(x.charAt(i) == '.') {
                    res = Long.parseLong(sb.toString());
                    sb = new StringBuilder("0");
                    dec = true;
                } else {
                    sb.append(x.charAt(i));
                    if(dec) f *= 10;
                }
            }
            res += Long.parseLong(sb.toString()) /f;
            return res * (neg ? -1 : 1);
        }
        public boolean ready() throws IOException { return br.ready(); }
    }
} public class Main {
    public static void main(String[] args) throws IOException {
        Scanner sc  = new Scanner(System.in);
        PrintWriter pw = new PrintWriter(System.out);
        String input = sc.next();
        if(input.contains("RRR")) pw.println(3);
        else if(input.contains("RR"))  pw.println(2);
        else if(input.contains("R")) pw.println(1);
        else pw.println(0);
        pw.close();
    }

    static class Scanner  {
        StringTokenizer st;
        BufferedReader br;

        public Scanner(InputStream s) {
            br  = new BufferedReader(new InputStreamReader(s));
        }

        public String next() throws IOException {
            while (st ==  null ||  !st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
            return st.nextToken();
        }

        public int nextInt() throws IOException { return Integer.parseInt(next()); }
        public long nextLong() throws IOException { return Long.parseLong(next()); }
        public String nextLine() throws IOException { return br.readLine(); }
        public double nextDouble() throws IOException {
            String x = next();
            StringBuilder sb  = new StringBuilder("0");
            double res = 0, f = 1;
            boolean dec = false, neg = false;
            int start = 0;
            if(x.charAt(0) == '-') {
                neg = true;
                start++;
            }
            for(int i = start; i < x.length(); i++) {
                if(x.charAt(i) == '.') {
                    res = Long.parseLong(sb.toString());
                    sb = new StringBuilder("0");
                    dec = true;
                } else {
                    sb.append(x.charAt(i));
                    if(dec) f *= 10;
                }
            }
            res += Long.parseLong(sb.toString()) /f;
            return res * (neg ? -1 : 1);
        }
        public boolean ready() throws IOException { return br.ready(); }
    }
} Main

import java.util.*;
import java.io.*;

public class Main {
    public static void main(String[] args) throws IOException {
        Scanner sc  = new Scanner(System.in);
        PrintWriter pw = new PrintWriter(System.out);
        String input = sc.next();
        if(input.contains("RRR")) pw.println(3);
        else if(input.contains("RR"))  pw.println(2);
        else if(input.contains("R")) pw.println(1);
        else pw.println(0);
        pw.close();
    }

    static class Scanner  {
        StringTokenizer st;
        BufferedReader br;

        public Scanner(InputStream s) {
            br  = new BufferedReader(new InputStreamReader(s));
        }

        public String next() throws IOException {
            while (st ==  null ||  !st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
            return st.nextToken();
        }

        public int nextInt() throws IOException { return Integer.parseInt(next()); }
        public long nextLong() throws IOException { return Long.parseLong(next()); }
        public String nextLine() throws IOException { return br.readLine(); }
        public double nextDouble() throws IOException {
            String x = next();
            StringBuilder sb  = new StringBuilder("0");
            double res = 0, f = 1;
            boolean dec = false, neg = false;
            int start = 0;
            if(x.charAt(0) == '-') {
                neg = true;
                start++;
            }
            for(int i = start; i < x.length(); i++) {
                if(x.charAt(i) == '.') {
                    res = Long.parseLong(sb.toString());
                    sb = new StringBuilder("0");
                    dec = true;
                } else {
                    sb.append(x.charAt(i));
                    if(dec) f *= 10;
                }
            }
            res += Long.parseLong(sb.toString()) /f;
            return res * (neg ? -1 : 1);
        }
        public boolean ready() throws IOException { return br.ready(); }
    }
}