import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    char[] s = sc.next().toCharArray();
    int tmp = 0;
    int ans = 0;
    for (char ss : s) {
      if (ss == 'R') {
        tmp++;
      } else {
        tmp = 0;
      }
      ans = Math.max(tmp, ans);
    }
    System.out.println(ans);
    sc.close();
  }
} import java.util.Scanner; Scanner java.util public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    char[] s = sc.next().toCharArray();
    int tmp = 0;
    int ans = 0;
    for (char ss : s) {
      if (ss == 'R') {
        tmp++;
      } else {
        tmp = 0;
      }
      ans = Math.max(tmp, ans);
    }
    System.out.println(ans);
    sc.close();
  }
} Main public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    char[] s = sc.next().toCharArray();
    int tmp = 0;
    int ans = 0;
    for (char ss : s) {
      if (ss == 'R') {
        tmp++;
      } else {
        tmp = 0;
      }
      ans = Math.max(tmp, ans);
    }
    System.out.println(ans);
    sc.close();
  } main {
    Scanner sc = new Scanner(System.in);
    char[] s = sc.next().toCharArray();
    int tmp = 0;
    int ans = 0;
    for (char ss : s) {
      if (ss == 'R') {
        tmp++;
      } else {
        tmp = 0;
      }
      ans = Math.max(tmp, ans);
    }
    System.out.println(ans);
    sc.close();
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) char[] s = sc.next().toCharArray(); s sc.next().toCharArray() sc.next().toCharArray sc.next() sc.next sc int tmp = 0; tmp 0 int ans = 0; ans 0 for (char ss : s) {
      if (ss == 'R') {
        tmp++;
      } else {
        tmp = 0;
      }
      ans = Math.max(tmp, ans);
    } char ss s {
      if (ss == 'R') {
        tmp++;
      } else {
        tmp = 0;
      }
      ans = Math.max(tmp, ans);
    } {
      if (ss == 'R') {
        tmp++;
      } else {
        tmp = 0;
      }
      ans = Math.max(tmp, ans);
    } if (ss == 'R') {
        tmp++;
      } else {
        tmp = 0;
      } ss == 'R' ss 'R' {
        tmp++;
      } tmp++ tmp {
        tmp = 0;
      } tmp = 0 tmp 0 ans = Math.max(tmp, ans) ans Math.max(tmp, ans) Math.max Math tmp ans System.out.println(ans) System.out.println System.out System System.out ans sc.close() sc.close sc String[] args args public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    char[] s = sc.next().toCharArray();
    int tmp = 0;
    int ans = 0;
    for (char ss : s) {
      if (ss == 'R') {
        tmp++;
      } else {
        tmp = 0;
      }
      ans = Math.max(tmp, ans);
    }
    System.out.println(ans);
    sc.close();
  }
} public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    char[] s = sc.next().toCharArray();
    int tmp = 0;
    int ans = 0;
    for (char ss : s) {
      if (ss == 'R') {
        tmp++;
      } else {
        tmp = 0;
      }
      ans = Math.max(tmp, ans);
    }
    System.out.println(ans);
    sc.close();
  }
} Main
import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    char[] s = sc.next().toCharArray();
    int tmp = 0;
    int ans = 0;
    for (char ss : s) {
      if (ss == 'R') {
        tmp++;
      } else {
        tmp = 0;
      }
      ans = Math.max(tmp, ans);
    }
    System.out.println(ans);
    sc.close();
  }
}
