import java.util.Scanner;

public class Main {
public static void main(String[] args){
Scanner scanner = new Scanner(System.in);
String string = scanner.next();
int len = string.length();
int r_len = len-1;
char ch[] = string.toCharArray();
long result = 0;
if(len <= 8){
for(int i = 0; i < len; i++){
if(ch[i] == ‘1’){
result += 1 * Math.pow(16, r_len);
}
if(ch[i] == ‘2’){
result += 2 * Math.pow(16, r_len);
}
if(ch[i] == ‘3’){
result += 3 * Math.pow(16, r_len);
}
if(ch[i] == ‘4’){
result += 4 * Math.pow(16, r_len);
}
if(ch[i] == ‘5’){
result += 5 * Math.pow(16, r_len);
}
if(ch[i] == ‘6’){
result += 6 * Math.pow(16, r_len);
}
if(ch[i] == ‘7’){
result += 7 * Math.pow(16, r_len);
}
if(ch[i] == ‘8’){
result += 8 * Math.pow(16, r_len);
}
if(ch[i] ==’9′){
result += 9 * Math.pow(16, r_len);
}
if(ch[i] == ‘A’){
result += 10 * Math.pow(16, r_len);
}
if(ch[i] == ‘B’){
result += 11 * Math.pow(16, r_len);
}
if(ch[i] == ‘C’){
result += 12 * Math.pow(16, r_len);
}
if(ch[i] == ‘D’){
result += 13 * Math.pow(16, r_len);
}
if(ch[i] == ‘E’){
result += 14 * Math.pow(16, r_len);
}
if(ch[i] == ‘F’){
result += 15 * Math.pow(16, r_len);
}
if(r_len > 0){
r_len–;
}
}
System.out.println(result);
}
scanner.close();
}
}