#include <stdio.h>
#include <stdint.h>
#define FIELD_MASK 0x1F
#define FIELD_POS 4U
#define EXTRACT_FIELD(x) ((x>>FIELD_POS) & FIELD_MASK)
uint8_t extract_field(uint16_t reg) {
// Your logic here
return EXTRACT_FIELD(reg);
}
int main() {
uint16_t reg;
scanf("%hx", ®);
printf("%u", extract_field(reg));
return 0;
}