#include <stdio.h>
#include <stdint.h>
uint32_t extract_even_bits(uint32_t reg) {
// Your code here
uint32_t res = 0;
for(uint8_t i = 0;i < sizeof(reg)*8/2;i++){
uint8_t bit = (reg>>(i*2))&1;
res |= (bit<<i);
}
return res;
}
int main() {
uint32_t reg;
scanf("%u", ®);
printf("%u", extract_even_bits(reg));
return 0;
}