import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
// import java.util.Arrays;
// import java.util.Random;
import java.util.StringTokenizer;

public class Main {
     public static void main(String[] args) {
         FastScanner fs=new FastScanner();
         int T=1;
         for (int tt=0; tt<T; tt++) {
                    String s = fs.next();
                    int maxc = 0;
                    int maxg = 0;
                    for(int i=0;i<s.length();i++){
                        if(s.charAt(i) == 'R'){
                            maxc++;
                            maxg = Math.max(maxc,maxg);
                        }
                        else{
                            maxc = 0;
                        }
                        
                    }
                    System.out.println(maxg);


                 }
}
 
 static class FastScanner {
     BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
     StringTokenizer st=new StringTokenizer("");
     String next() {
     while (!st.hasMoreTokens())
         try {
             st=new StringTokenizer(br.readLine());
         } catch (IOException e) {
             e.printStackTrace();
         }
         return st.nextToken();
     }
     
     int nextInt() {
         return Integer.parseInt(next());
     }
     int[] readArray(int n) {
         int[] a=new int[n];
         for (int i=0; i<n; i++) a[i]=nextInt();
         return a;
     }
     long nextLong() {
         return Long.parseLong(next());
     }
 }

 
} 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 public class Main {
     public static void main(String[] args) {
         FastScanner fs=new FastScanner();
         int T=1;
         for (int tt=0; tt<T; tt++) {
                    String s = fs.next();
                    int maxc = 0;
                    int maxg = 0;
                    for(int i=0;i<s.length();i++){
                        if(s.charAt(i) == 'R'){
                            maxc++;
                            maxg = Math.max(maxc,maxg);
                        }
                        else{
                            maxc = 0;
                        }
                        
                    }
                    System.out.println(maxg);


                 }
}
 
 static class FastScanner {
     BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
     StringTokenizer st=new StringTokenizer("");
     String next() {
     while (!st.hasMoreTokens())
         try {
             st=new StringTokenizer(br.readLine());
         } catch (IOException e) {
             e.printStackTrace();
         }
         return st.nextToken();
     }
     
     int nextInt() {
         return Integer.parseInt(next());
     }
     int[] readArray(int n) {
         int[] a=new int[n];
         for (int i=0; i<n; i++) a[i]=nextInt();
         return a;
     }
     long nextLong() {
         return Long.parseLong(next());
     }
 }

 
} Main public static void main(String[] args) {
         FastScanner fs=new FastScanner();
         int T=1;
         for (int tt=0; tt<T; tt++) {
                    String s = fs.next();
                    int maxc = 0;
                    int maxg = 0;
                    for(int i=0;i<s.length();i++){
                        if(s.charAt(i) == 'R'){
                            maxc++;
                            maxg = Math.max(maxc,maxg);
                        }
                        else{
                            maxc = 0;
                        }
                        
                    }
                    System.out.println(maxg);


                 }
} main {
         FastScanner fs=new FastScanner();
         int T=1;
         for (int tt=0; tt<T; tt++) {
                    String s = fs.next();
                    int maxc = 0;
                    int maxg = 0;
                    for(int i=0;i<s.length();i++){
                        if(s.charAt(i) == 'R'){
                            maxc++;
                            maxg = Math.max(maxc,maxg);
                        }
                        else{
                            maxc = 0;
                        }
                        
                    }
                    System.out.println(maxg);


                 }
} FastScanner fs=new FastScanner(); fs new FastScanner() int T=1; T 1 for (int tt=0; tt<T; tt++) {
                    String s = fs.next();
                    int maxc = 0;
                    int maxg = 0;
                    for(int i=0;i<s.length();i++){
                        if(s.charAt(i) == 'R'){
                            maxc++;
                            maxg = Math.max(maxc,maxg);
                        }
                        else{
                            maxc = 0;
                        }
                        
                    }
                    System.out.println(maxg);


                 } int tt=0; int tt=0; tt 0 tt<T tt T tt++ tt++ tt {
                    String s = fs.next();
                    int maxc = 0;
                    int maxg = 0;
                    for(int i=0;i<s.length();i++){
                        if(s.charAt(i) == 'R'){
                            maxc++;
                            maxg = Math.max(maxc,maxg);
                        }
                        else{
                            maxc = 0;
                        }
                        
                    }
                    System.out.println(maxg);


                 } {
                    String s = fs.next();
                    int maxc = 0;
                    int maxg = 0;
                    for(int i=0;i<s.length();i++){
                        if(s.charAt(i) == 'R'){
                            maxc++;
                            maxg = Math.max(maxc,maxg);
                        }
                        else{
                            maxc = 0;
                        }
                        
                    }
                    System.out.println(maxg);


                 } String s = fs.next(); s fs.next() fs.next fs int maxc = 0; maxc 0 int maxg = 0; maxg 0 for(int i=0;i<s.length();i++){
                        if(s.charAt(i) == 'R'){
                            maxc++;
                            maxg = Math.max(maxc,maxg);
                        }
                        else{
                            maxc = 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'){
                            maxc++;
                            maxg = Math.max(maxc,maxg);
                        }
                        else{
                            maxc = 0;
                        }
                        
                    } {
                        if(s.charAt(i) == 'R'){
                            maxc++;
                            maxg = Math.max(maxc,maxg);
                        }
                        else{
                            maxc = 0;
                        }
                        
                    } if(s.charAt(i) == 'R'){
                            maxc++;
                            maxg = Math.max(maxc,maxg);
                        }
                        else{
                            maxc = 0;
                        } s.charAt(i) == 'R' s.charAt(i) s.charAt s i 'R' {
                            maxc++;
                            maxg = Math.max(maxc,maxg);
                        } maxc++ maxc maxg = Math.max(maxc,maxg) maxg Math.max(maxc,maxg) Math.max Math maxc maxg {
                            maxc = 0;
                        } maxc = 0 maxc 0 System.out.println(maxg) System.out.println System.out System System.out maxg String[] args args static class FastScanner {
     BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
     StringTokenizer st=new StringTokenizer("");
     String next() {
     while (!st.hasMoreTokens())
         try {
             st=new StringTokenizer(br.readLine());
         } catch (IOException e) {
             e.printStackTrace();
         }
         return st.nextToken();
     }
     
     int nextInt() {
         return Integer.parseInt(next());
     }
     int[] readArray(int n) {
         int[] a=new int[n];
         for (int i=0; i<n; i++) a[i]=nextInt();
         return a;
     }
     long nextLong() {
         return Long.parseLong(next());
     }
 } FastScanner BufferedReader br=new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) StringTokenizer st=new StringTokenizer(""); st new StringTokenizer("") String next() {
     while (!st.hasMoreTokens())
         try {
             st=new StringTokenizer(br.readLine());
         } catch (IOException e) {
             e.printStackTrace();
         }
         return st.nextToken();
     } next {
     while (!st.hasMoreTokens())
         try {
             st=new StringTokenizer(br.readLine());
         } catch (IOException e) {
             e.printStackTrace();
         }
         return st.nextToken();
     } while (!st.hasMoreTokens())
         try {
             st=new StringTokenizer(br.readLine());
         } catch (IOException e) {
             e.printStackTrace();
         } !st.hasMoreTokens() st.hasMoreTokens() st.hasMoreTokens st 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 int[] readArray(int n) {
         int[] a=new int[n];
         for (int i=0; i<n; i++) a[i]=nextInt();
         return a;
     } readArray {
         int[] a=new int[n];
         for (int i=0; i<n; i++) a[i]=nextInt();
         return a;
     } int[] a=new int[n]; a new int[n] n for (int i=0; i<n; i++) a[i]=nextInt(); int i=0; int i=0; i 0 i<n i n i++ i++ i a[i]=nextInt(); a[i]=nextInt() a[i] a i nextInt() nextInt return a; a int n n long nextLong() {
         return Long.parseLong(next());
     } nextLong {
         return Long.parseLong(next());
     } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next public class Main {
     public static void main(String[] args) {
         FastScanner fs=new FastScanner();
         int T=1;
         for (int tt=0; tt<T; tt++) {
                    String s = fs.next();
                    int maxc = 0;
                    int maxg = 0;
                    for(int i=0;i<s.length();i++){
                        if(s.charAt(i) == 'R'){
                            maxc++;
                            maxg = Math.max(maxc,maxg);
                        }
                        else{
                            maxc = 0;
                        }
                        
                    }
                    System.out.println(maxg);


                 }
}
 
 static class FastScanner {
     BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
     StringTokenizer st=new StringTokenizer("");
     String next() {
     while (!st.hasMoreTokens())
         try {
             st=new StringTokenizer(br.readLine());
         } catch (IOException e) {
             e.printStackTrace();
         }
         return st.nextToken();
     }
     
     int nextInt() {
         return Integer.parseInt(next());
     }
     int[] readArray(int n) {
         int[] a=new int[n];
         for (int i=0; i<n; i++) a[i]=nextInt();
         return a;
     }
     long nextLong() {
         return Long.parseLong(next());
     }
 }

 
} public class Main {
     public static void main(String[] args) {
         FastScanner fs=new FastScanner();
         int T=1;
         for (int tt=0; tt<T; tt++) {
                    String s = fs.next();
                    int maxc = 0;
                    int maxg = 0;
                    for(int i=0;i<s.length();i++){
                        if(s.charAt(i) == 'R'){
                            maxc++;
                            maxg = Math.max(maxc,maxg);
                        }
                        else{
                            maxc = 0;
                        }
                        
                    }
                    System.out.println(maxg);


                 }
}
 
 static class FastScanner {
     BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
     StringTokenizer st=new StringTokenizer("");
     String next() {
     while (!st.hasMoreTokens())
         try {
             st=new StringTokenizer(br.readLine());
         } catch (IOException e) {
             e.printStackTrace();
         }
         return st.nextToken();
     }
     
     int nextInt() {
         return Integer.parseInt(next());
     }
     int[] readArray(int n) {
         int[] a=new int[n];
         for (int i=0; i<n; i++) a[i]=nextInt();
         return a;
     }
     long nextLong() {
         return Long.parseLong(next());
     }
 }

 
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
// import java.util.Arrays;
// import java.util.Random;
import java.util.StringTokenizer;

public class Main {
     public static void main(String[] args) {
         FastScanner fs=new FastScanner();
         int T=1;
         for (int tt=0; tt<T; tt++) {
                    String s = fs.next();
                    int maxc = 0;
                    int maxg = 0;
                    for(int i=0;i<s.length();i++){
                        if(s.charAt(i) == 'R'){
                            maxc++;
                            maxg = Math.max(maxc,maxg);
                        }
                        else{
                            maxc = 0;
                        }
                        
                    }
                    System.out.println(maxg);


                 }
}
 
 static class FastScanner {
     BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
     StringTokenizer st=new StringTokenizer("");
     String next() {
     while (!st.hasMoreTokens())
         try {
             st=new StringTokenizer(br.readLine());
         } catch (IOException e) {
             e.printStackTrace();
         }
         return st.nextToken();
     }
     
     int nextInt() {
         return Integer.parseInt(next());
     }
     int[] readArray(int n) {
         int[] a=new int[n];
         for (int i=0; i<n; i++) a[i]=nextInt();
         return a;
     }
     long nextLong() {
         return Long.parseLong(next());
     }
 }

 
}
