#include <time.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>

struct tm *
psbody(int fd)
{
    time_t t;
    read(fd, &t, sizeof(t));
    close(fd);
    struct tm *stm = localtime(&t);
    return stm;
}

int
main(void)
{
    int fds[2];
    pipe(fds);
    time_t t = time(NULL);
    write(fds[1], &t, sizeof(t));
    write(fds[1], &t, sizeof(t));
    write(fds[1], &t, sizeof(t));
    pid_t ps;
    if (!(ps = fork())) {
        close(fds[1]);
        pid_t pg;
        if (!(pg = fork())) {
            pid_t pgg;
            if (!(pgg = fork())) {
                struct tm *stmgg = psbody(fds[0]);
                printf("S:%02d\n", stmgg->tm_sec);
                _exit(0);
            }
            waitpid(pgg, NULL, 0);
            struct tm *stmg = psbody(fds[0]);
            printf("M:%02d\n", stmg->tm_min);
            _exit(0);
        }
        waitpid(pg, NULL, 0);
        struct tm *stms = psbody(fds[0]);
        printf("H:%02d\n", stms->tm_hour);
        _exit(0);
    }
    waitpid(ps, NULL, 0);
    close(fds[0]);
    close(fds[1]);
    return 0;
}