#include <stdio.h>
#include <stdint.h>
uint32_t extract_even_bits(uint32_t reg) {
// Your code here
uint32_t val = 0;
while(reg!=0)
{
val <<= 1;
val = (val | (reg&1));
reg >>= 2;
}
return val;
}
int main() {
uint32_t reg;
scanf("%u", ®);
printf("%u", extract_even_bits(reg));
return 0;
}