#include <stdio.h>
#include <stdint.h>
uint32_t extract_even_bits(uint32_t reg) {
int result = 0;
while(reg){
result = result << 1;
result |= (reg&(0x01));
reg = reg>>2 ;
}
return result;
}
int main() {
uint32_t reg;
scanf("%u", ®);
printf("%u", extract_even_bits(reg));
return 0;
}