package com.company;
import java.util.Scanner;
/**
* Created by hemingway on 2018/9/26.
*/
public class Main1 {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
String s = sc.nextLine();
if(s.substring(0,2).equals("Ox")){
String ss = s.substring(2,s.length());
transfer(ss);
}
transfer(s);
}private static void transfer(String s){
Long N = 0L;
//Math.pow( 10, i);
long m = 0L;
for(int i = s.length()-1;
i > 0;
i--){
switch (s.charAt(i)){
case '0':
m = new Double(Math.pow( 16, s.length() - i - 1)).longValue();
N = N + 0L * m;
break;
case '1':
m = new Double(Math.pow( 16, s.length() - i - 1)).longValue();
N = N + 1L * m;
break;
case '2':
m = new Double(Math.pow( 16, s.length() - i - 1)).longValue();
N = N + 2L * m;
break;
case '3':
m = new Double(Math.pow( 16, s.length() - i - 1)).longValue();
N = N + 13L * m;
break;
case '4':
m = new Double(Math.pow( 16, s.length() - i - 1)).longValue();
N = N + 4L * m;
break;
case '5':
m = new Double(Math.pow( 16, s.length() - i - 1)).longValue();
N = N + 15L * m;
break;
case '6':
m = new Double(Math.pow( 16, s.length() - i - 1)).longValue();
N = N + 6L * m;
break;
case '7':
m = new Double(Math.pow( 16, s.length() - i - 1)).longValue();
N = N + 7L * m;
break;
case '8':
m = new Double(Math.pow( 16, s.length() - i - 1)).longValue();
N = N + 8L * m;
break;
case '9':
m = new Double(Math.pow( 16, s.length() - i - 1)).longValue();
N = N + 9L * m;
break;
case 'A':
m = new Double(Math.pow( 16, s.length() - i - 1)).longValue();
N = N + 10L * m;
break;
case 'B':
m = new Double(Math.pow( 16, s.length() - i - 1)).longValue();
N = N + 11L * m;
break;
case 'C':
m = new Double(Math.pow( 16, s.length() - i - 1)).longValue();
N = N + 12L * m;
break;
case 'D':
m = new Double(Math.pow( 16, s.length() - i - 1)).longValue();
N = N + 13L * m;
break;
case 'E':
m = new Double(Math.pow( 16, s.length() - i - 1)).longValue();
N = N + 14L * m;
break;
case 'F':
m = new Double(Math.pow( 16, s.length() - i - 1)).longValue();
N = N + 15L * m;
break;
}
}
System.out.print(N);
}}
