source_code: import java.math.BigInteger;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.GregorianCalendar;
  import java.util.Scanner;
  
  
  public class ProblemB {
  
      
      public static void main(String[] args) {
          Scanner s = new Scanner(System.in);
          
          int a = s.nextInt();
          
          int f1 = a/10;
          
          int b = a;
          int last = a%10;
          
          b/=10;
          b/=10;
          b*=10;
          b+=last;
          
          System.out.println(Math.max(a, Math.max(f1, b)));
          
          
          
      }
  
  }
  