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