#include <stdio.h>
#include <stdint.h>
uint16_t hex_to_uint(const char *str) {
// Your logic here
uint16_t result = 0;
for(int i=0;str[i]!='\0';i++){
result*=16;
if(str[i]>='a' && str[i]<='f')
result += str[i]-'a'+10;
else if(str[i]>='A' && str[i]<='F')
result += str[i]-'A'+10;
else
{
result += str[i]-'0';
}
}
return result;
}
int main() {
char hex[10];
scanf("%s", hex);
printf("%u", hex_to_uint(hex));
return 0;
}