source_code: import java.util.*;
  
  public class Main{
  
      void solve(){
          Scanner sc = new Scanner(System.in);
  
          int n = sc.nextInt();
          int n1 = n/10;
          int n2 = n/100*10 + n%10;
  
          int ans = n;
          ans = Math.max(ans, n1);
          ans = Math.max(ans, n2);
          System.out.println(ans);
      }
  
      public static void main(String[] args){
          new Main().solve();
      }
  }
  