#include<sys/types.h>
#include<stdio.h>
#include<unistd.h>
int main(void){
pid_t x,y;

fork();
printf("A-Process ID : %d\n",getpid());
printf("B-Process ID : %d\n",getpid());
fork();
printf("C-Process ID : %d\n",getpid());
printf("D-Process ID : %d\n\n",getpid());
sleep(50);
return 0;}