#include <stdio.h>
#include <stdint.h>
uint16_t hex_to_uint(const char *str) {
uint16_t val=0;
for(int i=0;str[i];i++){
char c=str[i];
int digit;
if( c>='0'&&c<='9'){
digit = c-'0';
}else if( c>='A'&&c<='F'){
digit = c-'A'+10;
}else if(c >= 'a' && c <= 'f' ){
digit= c-'a'+10;
}else{
continue;
}
val=(val<<4)|uint16_t(digit);
}
return val;
}
int main() {
char hex[10];
scanf("%s", hex);
printf("%u", hex_to_uint(hex));
return 0;
}