source_code: import java.io.BufferedReader;
  import java.io.BufferedWriter;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.OutputStreamWriter;
  import java.io.PrintWriter;
  import java.util.ArrayList;
  import java.util.Map;
  import java.util.StringTokenizer;
  import java.util.TreeMap;
  
  public class A {
      private static BufferedReader in;
      private static StringTokenizer st;
      private static PrintWriter out;
      
      public static void main(String[] args) throws NumberFormatException, IOException {
          in = new BufferedReader(new InputStreamReader(System.in));
          st = new StringTokenizer("");
          out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
          int n = nextInt();
          int max = n;
          max = Math.max(max, n / 10);
          max = Math.max(max, (n / 100) * 10 + n % 10);
          System.out.println(max);
      }
      
  
      static String next() throws IOException{
          while(!st.hasMoreTokens()){
              st = new StringTokenizer(in.readLine());
          }
          return st.nextToken();
      }
      static int nextInt() throws NumberFormatException, IOException{
          return Integer.parseInt(next());
      }
      static long nextLong() throws NumberFormatException, IOException{
          return Long.parseLong(next());
      }
      
      static double nextDouble() throws NumberFormatException, IOException{
          return Double.parseDouble(next());
      }
  
  }
  