#include <stdio.h>
#include <stdint.h>
uint16_t hex_to_uint(const char *str) {
// Your logic here
int result =0;
while(*str !='\0'){
result<<=4;
if(*str>='0'&&*str<='9'){
result+=*str-'0';
str++;
}
else if(*str>='A'&&*str<='F'){
result+= *str-'A'+10;
str++;
}
else if(*str >='a'&& *str <='f'){
result += *str-'a'+10;str++;
}
else
str++;
}
return result;
}
int main() {
char hex[10];
scanf("%s", hex);
printf("%u", hex_to_uint(hex));
return 0;
}