source_code: 
  
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  
  
  
  public class BankAccount {
  
  	/**
  	 * @param args
  	 * @throws IOException 
  	 */
  	public static void main(String[] args) throws IOException {
  		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
  
  		String s = in.readLine();
  		int n = Integer.parseInt(s);
  
  		if (s.charAt(0) == '-')
  			if (Integer.parseInt(s.substring(0, s.length()-1))>Integer.parseInt(s.substring(0, s.length()-2)+s.charAt(s.length()-1)))
  				s=s.substring(0, s.length()-1);
  			else
  				s=s.substring(0, s.length()-2)+s.charAt(s.length()-1);
  
  		System.out.println(Integer.parseInt(s));
  		in.close();
  	}
  
  }
  