#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <unistd.h>
 
int main(void){
 
    if(fork()==0){
        printf("Child process started. pid = %d\n",getpid());
        if (fork() ==0) {
        	printf("Grand child process started. pid = %d\n", getpid());
        	sleep(5);
        	printf("Grandchild process end.\n");
        }
        sleep(1);
        printf("Child process end.\n");
    }
 
    pid_t pid = wait(0);
 
    printf("%d is waiting child. pid = %d\n", getpid(), pid);
    return 0;
}

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