source_code: import java.io.*;
  import java.util.*;
  import java.math.*;
  
  public class A {
      public static void main(String[] args) { 
          OutputStream outputStream = System.out;
          PrintWriter out = new PrintWriter(outputStream);
  
          Application solver = new Application();
          solver.solve(System.in, out);
  
          out.close();
      }
  }
  
  
  class Application {
      int max(int a, int b) { return a > b ? a : b; }
      public void solve(InputStream in, PrintWriter out) {
          Scanner scanner = new Scanner(in);
  
          int n = scanner.nextInt();
          int n1 = n/10;
          int n2 = (n/100)*10+(n%10);
          int m = max(max(n1, n2), n);
  
          out.println(m);
      }
  }
  