import java.util.Scanner;
import java.util.List;
import java.util.Collections;
import java.util.ArrayList;
// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
String a = in.nextLine();
String []b = a.split(" ");
List<String>list = new ArrayList<>();
//获取字符串
for (String b1 : b) {//遍历字符串
String c = b1.substring(2).toUpperCase();//截取字符串并转换成大写
list.add(c);//添加到list集合中
}
for (int i = 0; i < list.size(); i++) {
Collections.reverse(list);//翻转list集合中的元素
char []chars = list.get(i).toCharArray(); //转换成char数组
for (int j = 0; j < chars.length; j++) {
int decimal = 0;
int power = 0; // 对应16^0、16^1、16^2...
for (int k = chars.length - 1; k >= 0; k--) { // 倒序遍历
char c = chars[k];
if (c >= '0' && c <= '9' || c >= 'A' && c <= 'F') {
decimal += (c <= '9' ? c - '0' : c - 'A' + 10) * (int) Math.pow(16, power);
power++;
}
}
System.out.println(decimal);
break;
}
}
}
}