package com.cg.helloworld;

import java.util.Scanner;

public class Exercise1 {
    public static void main(String[] args){
        Scanner a=new Scanner(System.in);
        int b=a.nextInt();
        if(b<=0){
            System.out.println("-1");
        }
        else{
            int[] array1=new int[3];
            array1[2]=(b-b%100)/100;
            array1[1]=(b%100-b%10)/10;
            array1[0]=b%10;
            if(array1[0]==0 && array1[1]==0 )
                System.out.print(array1[2]);
            else if(array1[0]==0 && array1[1]!=0){
                System.out.print(array1[1]);
                System.out.print(array1[2]);
            }
            else {for (int k:array1
            ) {
                System.out.print(k);
            }
            }
        };

}
}