import java.io.*;
import java.math.*;
import java.util.*;
 
public class Main {
	static final long MOD = 1000000007L;
	public static void main(String[] args) {
		FastScanner sc = new FastScanner();
		PrintWriter pw = new PrintWriter(System.out);
		
		String s = sc.next();
		int ans = 0;
		int cur = 0;
		for (int i = 0; i < s.length(); i++) {
			if (s.charAt(i)=='R') {
				cur++;
			} else {
				ans = Math.max(ans, cur);
				cur = 0;
			}
		}
		ans = Math.max(ans, cur);
		pw.println(ans);
		
		pw.close();
	}
	
    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 ni() { 
            return Integer.parseInt(next()); 
        }
  
        long nl() { 
            return Long.parseLong(next()); 
        } 
  
        double nd() { 
            return Double.parseDouble(next()); 
        } 
  
        String nextLine() {
            String str = ""; 
            try { 
                str = br.readLine(); 
            } catch (IOException e) {
                e.printStackTrace(); 
            } 
            return str;
        }
    }
} import java.io.*; io.* java import java.math.*; math.* java import java.util.*; util.* java public class Main {
	static final long MOD = 1000000007L;
	public static void main(String[] args) {
		FastScanner sc = new FastScanner();
		PrintWriter pw = new PrintWriter(System.out);
		
		String s = sc.next();
		int ans = 0;
		int cur = 0;
		for (int i = 0; i < s.length(); i++) {
			if (s.charAt(i)=='R') {
				cur++;
			} else {
				ans = Math.max(ans, cur);
				cur = 0;
			}
		}
		ans = Math.max(ans, cur);
		pw.println(ans);
		
		pw.close();
	}
	
    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 ni() { 
            return Integer.parseInt(next()); 
        }
  
        long nl() { 
            return Long.parseLong(next()); 
        } 
  
        double nd() { 
            return Double.parseDouble(next()); 
        } 
  
        String nextLine() {
            String str = ""; 
            try { 
                str = br.readLine(); 
            } catch (IOException e) {
                e.printStackTrace(); 
            } 
            return str;
        }
    }
} Main static final long MOD = 1000000007L; MOD 1000000007L public static void main(String[] args) {
		FastScanner sc = new FastScanner();
		PrintWriter pw = new PrintWriter(System.out);
		
		String s = sc.next();
		int ans = 0;
		int cur = 0;
		for (int i = 0; i < s.length(); i++) {
			if (s.charAt(i)=='R') {
				cur++;
			} else {
				ans = Math.max(ans, cur);
				cur = 0;
			}
		}
		ans = Math.max(ans, cur);
		pw.println(ans);
		
		pw.close();
	} main {
		FastScanner sc = new FastScanner();
		PrintWriter pw = new PrintWriter(System.out);
		
		String s = sc.next();
		int ans = 0;
		int cur = 0;
		for (int i = 0; i < s.length(); i++) {
			if (s.charAt(i)=='R') {
				cur++;
			} else {
				ans = Math.max(ans, cur);
				cur = 0;
			}
		}
		ans = Math.max(ans, cur);
		pw.println(ans);
		
		pw.close();
	} FastScanner sc = new FastScanner(); sc new FastScanner() PrintWriter pw = new PrintWriter(System.out); pw new PrintWriter(System.out) String s = sc.next(); s sc.next() sc.next sc int ans = 0; ans 0 int cur = 0; cur 0 for (int i = 0; i < s.length(); i++) {
			if (s.charAt(i)=='R') {
				cur++;
			} else {
				ans = Math.max(ans, cur);
				cur = 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') {
				cur++;
			} else {
				ans = Math.max(ans, cur);
				cur = 0;
			}
		} {
			if (s.charAt(i)=='R') {
				cur++;
			} else {
				ans = Math.max(ans, cur);
				cur = 0;
			}
		} if (s.charAt(i)=='R') {
				cur++;
			} else {
				ans = Math.max(ans, cur);
				cur = 0;
			} s.charAt(i)=='R' s.charAt(i) s.charAt s i 'R' {
				cur++;
			} cur++ cur {
				ans = Math.max(ans, cur);
				cur = 0;
			} ans = Math.max(ans, cur) ans Math.max(ans, cur) Math.max Math ans cur cur = 0 cur 0 ans = Math.max(ans, cur) ans Math.max(ans, cur) Math.max Math ans cur pw.println(ans) pw.println pw ans pw.close() pw.close pw 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 ni() { 
            return Integer.parseInt(next()); 
        }
  
        long nl() { 
            return Long.parseLong(next()); 
        } 
  
        double nd() { 
            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 ni() { 
            return Integer.parseInt(next()); 
        } ni { 
            return Integer.parseInt(next()); 
        } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nl() { 
            return Long.parseLong(next()); 
        } nl { 
            return Long.parseLong(next()); 
        } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next double nd() { 
            return Double.parseDouble(next()); 
        } nd { 
            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 {
	static final long MOD = 1000000007L;
	public static void main(String[] args) {
		FastScanner sc = new FastScanner();
		PrintWriter pw = new PrintWriter(System.out);
		
		String s = sc.next();
		int ans = 0;
		int cur = 0;
		for (int i = 0; i < s.length(); i++) {
			if (s.charAt(i)=='R') {
				cur++;
			} else {
				ans = Math.max(ans, cur);
				cur = 0;
			}
		}
		ans = Math.max(ans, cur);
		pw.println(ans);
		
		pw.close();
	}
	
    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 ni() { 
            return Integer.parseInt(next()); 
        }
  
        long nl() { 
            return Long.parseLong(next()); 
        } 
  
        double nd() { 
            return Double.parseDouble(next()); 
        } 
  
        String nextLine() {
            String str = ""; 
            try { 
                str = br.readLine(); 
            } catch (IOException e) {
                e.printStackTrace(); 
            } 
            return str;
        }
    }
} public class Main {
	static final long MOD = 1000000007L;
	public static void main(String[] args) {
		FastScanner sc = new FastScanner();
		PrintWriter pw = new PrintWriter(System.out);
		
		String s = sc.next();
		int ans = 0;
		int cur = 0;
		for (int i = 0; i < s.length(); i++) {
			if (s.charAt(i)=='R') {
				cur++;
			} else {
				ans = Math.max(ans, cur);
				cur = 0;
			}
		}
		ans = Math.max(ans, cur);
		pw.println(ans);
		
		pw.close();
	}
	
    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 ni() { 
            return Integer.parseInt(next()); 
        }
  
        long nl() { 
            return Long.parseLong(next()); 
        } 
  
        double nd() { 
            return Double.parseDouble(next()); 
        } 
  
        String nextLine() {
            String str = ""; 
            try { 
                str = br.readLine(); 
            } catch (IOException e) {
                e.printStackTrace(); 
            } 
            return str;
        }
    }
} Main
import java.io.*;
import java.math.*;
import java.util.*;
 
public class Main {
	static final long MOD = 1000000007L;
	public static void main(String[] args) {
		FastScanner sc = new FastScanner();
		PrintWriter pw = new PrintWriter(System.out);
		
		String s = sc.next();
		int ans = 0;
		int cur = 0;
		for (int i = 0; i < s.length(); i++) {
			if (s.charAt(i)=='R') {
				cur++;
			} else {
				ans = Math.max(ans, cur);
				cur = 0;
			}
		}
		ans = Math.max(ans, cur);
		pw.println(ans);
		
		pw.close();
	}
	
    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 ni() { 
            return Integer.parseInt(next()); 
        }
  
        long nl() { 
            return Long.parseLong(next()); 
        } 
  
        double nd() { 
            return Double.parseDouble(next()); 
        } 
  
        String nextLine() {
            String str = ""; 
            try { 
                str = br.readLine(); 
            } catch (IOException e) {
                e.printStackTrace(); 
            } 
            return str;
        }
    }
}