source_code: import java.util.*;
  
  public class ex1 {
  	
  	public static void main(String[] args)	{
  		int n,i,j;
  		Scanner scan = new Scanner(System.in);
  		n = Integer.parseInt(scan.nextLine());
  		if(n>=0)
  			System.out.println(n);
  		else if(n<0)	{
  			n=-1*n;
  			i=n/10;
  			j=(n/100)*10+n%10;
  			i=-i;
  			j=-j;
  			if(i>=j)
  				System.out.println(i);
  			else
  				System.out.println(j);
  		}
  	}
  	
  }
  