#include <stdio.h>
#include <stdint.h>
uint8_t extract_field(uint16_t reg) {
// Your logic here
uint16_t mask;
uint8_t field;
mask = ((1<<5)-1) << 4;
field = (reg & mask) >> 4;
return field;
}
int main() {
uint16_t reg;
scanf("%hx", ®);
printf("%u", extract_field(reg));
return 0;
}