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