#include <stdio.h>
#include <stdint.h>
uint32_t replace_field(uint32_t reg, uint32_t val, uint8_t pos, uint8_t len) {
// Your code here
int POS=0;
for(int pos1=pos;pos1<(pos+len);pos1++,POS++)
{
if((reg>>pos1&1)!=(val>>POS&1))
reg=reg^(1<<pos1);
}
return reg;
}
int main() {
uint32_t reg, val;
uint8_t pos, len;
scanf("%u %u %hhu %hhu", ®, &val, &pos, &len);
printf("%u", replace_field(reg, val, pos, len));
return 0;
}