source_code: 
  /**
   *
   * @author saurabh
   */
  public class myTemplate {
  
      /**
       * @param args the command line arguments
       */
      public static void main(String[] args) throws Exception{
          // TODO code application logic here
         java.io.BufferedReader br = new java.io.BufferedReader(new 
                   java.io.InputStreamReader(System.in));
         
         int ch[],arr[];
         int x,i,j,k,t,n=Integer.parseInt(br.readLine());
          //System.out.println(n);
          
         if(n>0)
              System.out.println(n);
         else
         {
             //n= -n;
             //n=-n;
             x= n/100;
             
             x = x*10 + n%10;
           //  System.out.println(x);
             if(n/10 > x)
                 System.out.println(n/10);
             else
                System.out.println(x);
             
         }
         
      }
  }
  