import java.util.*;
import java.io.*;
public class Main {

	public static void main(String[] args) {
		FastScanner fs = new FastScanner();
		String s = fs.nextLine();
		int c=0,max=0;
		for(int i=0;i<s.length();i++)
		{
			
			if(s.charAt(i)=='R')
			{
				c++;
				max = Math.max(max, c);
			}
			else
			{
				c=0;
			}
			
		}
		System.out.println(max);

	}

	
	
	
	
	
	
	static class FastScanner
    { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastScanner() 
        { 
            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) {
		FastScanner fs = new FastScanner();
		String s = fs.nextLine();
		int c=0,max=0;
		for(int i=0;i<s.length();i++)
		{
			
			if(s.charAt(i)=='R')
			{
				c++;
				max = Math.max(max, c);
			}
			else
			{
				c=0;
			}
			
		}
		System.out.println(max);

	}

	
	
	
	
	
	
	static class FastScanner
    { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastScanner() 
        { 
            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) {
		FastScanner fs = new FastScanner();
		String s = fs.nextLine();
		int c=0,max=0;
		for(int i=0;i<s.length();i++)
		{
			
			if(s.charAt(i)=='R')
			{
				c++;
				max = Math.max(max, c);
			}
			else
			{
				c=0;
			}
			
		}
		System.out.println(max);

	} main {
		FastScanner fs = new FastScanner();
		String s = fs.nextLine();
		int c=0,max=0;
		for(int i=0;i<s.length();i++)
		{
			
			if(s.charAt(i)=='R')
			{
				c++;
				max = Math.max(max, c);
			}
			else
			{
				c=0;
			}
			
		}
		System.out.println(max);

	} FastScanner fs = new FastScanner(); fs new FastScanner() String s = fs.nextLine(); s fs.nextLine() fs.nextLine fs int c=0 c 0 max=0; max 0 for(int i=0;i<s.length();i++)
		{
			
			if(s.charAt(i)=='R')
			{
				c++;
				max = Math.max(max, c);
			}
			else
			{
				c=0;
			}
			
		} int i=0; int i=0; i 0 i<s.length() i s.length() s.length s i++ i++ i {
			
			if(s.charAt(i)=='R')
			{
				c++;
				max = Math.max(max, c);
			}
			else
			{
				c=0;
			}
			
		} {
			
			if(s.charAt(i)=='R')
			{
				c++;
				max = Math.max(max, c);
			}
			else
			{
				c=0;
			}
			
		} if(s.charAt(i)=='R')
			{
				c++;
				max = Math.max(max, c);
			}
			else
			{
				c=0;
			} s.charAt(i)=='R' s.charAt(i) s.charAt s i 'R' {
				c++;
				max = Math.max(max, c);
			} c++ c max = Math.max(max, c) max Math.max(max, c) Math.max Math max c {
				c=0;
			} c=0 c 0 System.out.println(max) System.out.println System.out System System.out max String[] args args static class FastScanner
    { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastScanner() 
        { 
            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; 
        } 
    } FastScanner BufferedReader br; br StringTokenizer st; st public FastScanner() 
        { 
            br = new BufferedReader(new
                     InputStreamReader(System.in)); 
        } FastScanner { 
            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) {
		FastScanner fs = new FastScanner();
		String s = fs.nextLine();
		int c=0,max=0;
		for(int i=0;i<s.length();i++)
		{
			
			if(s.charAt(i)=='R')
			{
				c++;
				max = Math.max(max, c);
			}
			else
			{
				c=0;
			}
			
		}
		System.out.println(max);

	}

	
	
	
	
	
	
	static class FastScanner
    { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastScanner() 
        { 
            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) {
		FastScanner fs = new FastScanner();
		String s = fs.nextLine();
		int c=0,max=0;
		for(int i=0;i<s.length();i++)
		{
			
			if(s.charAt(i)=='R')
			{
				c++;
				max = Math.max(max, c);
			}
			else
			{
				c=0;
			}
			
		}
		System.out.println(max);

	}

	
	
	
	
	
	
	static class FastScanner
    { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastScanner() 
        { 
            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) {
		FastScanner fs = new FastScanner();
		String s = fs.nextLine();
		int c=0,max=0;
		for(int i=0;i<s.length();i++)
		{
			
			if(s.charAt(i)=='R')
			{
				c++;
				max = Math.max(max, c);
			}
			else
			{
				c=0;
			}
			
		}
		System.out.println(max);

	}

	
	
	
	
	
	
	static class FastScanner
    { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastScanner() 
        { 
            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; 
        } 
    }
	
	
	
	
}
