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

public class Main {
    public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out));
        String s = sc.next();
        int ans = 0; int run = 0;
        for (int i = 0; i < 3; i++) {
            if (s.charAt(i) == 'R') {
                run++;
            } else {
                ans = Math.max(ans, run);
              	run = 0;
            }
        }
        ans = Math.max(ans, run);
        out.println(ans);
        out.close();
    }


    //-----------MyScanner class for faster input----------
    public static class MyScanner {
        BufferedReader br;
        StringTokenizer st;

        public MyScanner() {
            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;
        }


    }

} import java.util.*; util.* java import java.io.*; io.* java public class Main {
    public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out));
        String s = sc.next();
        int ans = 0; int run = 0;
        for (int i = 0; i < 3; i++) {
            if (s.charAt(i) == 'R') {
                run++;
            } else {
                ans = Math.max(ans, run);
              	run = 0;
            }
        }
        ans = Math.max(ans, run);
        out.println(ans);
        out.close();
    }


    //-----------MyScanner class for faster input----------
    public static class MyScanner {
        BufferedReader br;
        StringTokenizer st;

        public MyScanner() {
            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;
        }


    }

} Main public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out));
        String s = sc.next();
        int ans = 0; int run = 0;
        for (int i = 0; i < 3; i++) {
            if (s.charAt(i) == 'R') {
                run++;
            } else {
                ans = Math.max(ans, run);
              	run = 0;
            }
        }
        ans = Math.max(ans, run);
        out.println(ans);
        out.close();
    } main {
        MyScanner sc = new MyScanner();
        PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out));
        String s = sc.next();
        int ans = 0; int run = 0;
        for (int i = 0; i < 3; i++) {
            if (s.charAt(i) == 'R') {
                run++;
            } else {
                ans = Math.max(ans, run);
              	run = 0;
            }
        }
        ans = Math.max(ans, run);
        out.println(ans);
        out.close();
    } MyScanner sc = new MyScanner(); sc new MyScanner() PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out)); out new PrintWriter(new BufferedOutputStream(System.out)) String s = sc.next(); s sc.next() sc.next sc int ans = 0; ans 0 int run = 0; run 0 for (int i = 0; i < 3; i++) {
            if (s.charAt(i) == 'R') {
                run++;
            } else {
                ans = Math.max(ans, run);
              	run = 0;
            }
        } int i = 0; int i = 0; i 0 i < 3 i 3 i++ i++ i {
            if (s.charAt(i) == 'R') {
                run++;
            } else {
                ans = Math.max(ans, run);
              	run = 0;
            }
        } {
            if (s.charAt(i) == 'R') {
                run++;
            } else {
                ans = Math.max(ans, run);
              	run = 0;
            }
        } if (s.charAt(i) == 'R') {
                run++;
            } else {
                ans = Math.max(ans, run);
              	run = 0;
            } s.charAt(i) == 'R' s.charAt(i) s.charAt s i 'R' {
                run++;
            } run++ run {
                ans = Math.max(ans, run);
              	run = 0;
            } ans = Math.max(ans, run) ans Math.max(ans, run) Math.max Math ans run run = 0 run 0 ans = Math.max(ans, run) ans Math.max(ans, run) Math.max Math ans run out.println(ans) out.println out ans out.close() out.close out String[] args args public static class MyScanner {
        BufferedReader br;
        StringTokenizer st;

        public MyScanner() {
            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;
        }


    } MyScanner BufferedReader br; br StringTokenizer st; st public MyScanner() {
            br = new BufferedReader(new InputStreamReader(System.in));
        } MyScanner {
            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 public class Main {
    public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out));
        String s = sc.next();
        int ans = 0; int run = 0;
        for (int i = 0; i < 3; i++) {
            if (s.charAt(i) == 'R') {
                run++;
            } else {
                ans = Math.max(ans, run);
              	run = 0;
            }
        }
        ans = Math.max(ans, run);
        out.println(ans);
        out.close();
    }


    //-----------MyScanner class for faster input----------
    public static class MyScanner {
        BufferedReader br;
        StringTokenizer st;

        public MyScanner() {
            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;
        }


    }

} public class Main {
    public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out));
        String s = sc.next();
        int ans = 0; int run = 0;
        for (int i = 0; i < 3; i++) {
            if (s.charAt(i) == 'R') {
                run++;
            } else {
                ans = Math.max(ans, run);
              	run = 0;
            }
        }
        ans = Math.max(ans, run);
        out.println(ans);
        out.close();
    }


    //-----------MyScanner class for faster input----------
    public static class MyScanner {
        BufferedReader br;
        StringTokenizer st;

        public MyScanner() {
            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;
        }


    }

} Main
import java.util.*;
import java.io.*;

public class Main {
    public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out));
        String s = sc.next();
        int ans = 0; int run = 0;
        for (int i = 0; i < 3; i++) {
            if (s.charAt(i) == 'R') {
                run++;
            } else {
                ans = Math.max(ans, run);
              	run = 0;
            }
        }
        ans = Math.max(ans, run);
        out.println(ans);
        out.close();
    }


    //-----------MyScanner class for faster input----------
    public static class MyScanner {
        BufferedReader br;
        StringTokenizer st;

        public MyScanner() {
            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;
        }


    }

}