#include <unistd.h>
#include <fcntl.h>
#include <sys/wait.h>

int
main(int argc, char *argv[])
{
    pid_t pid, pid1;
    int fd, status;
    int fds[2];
    if (pipe(fds) == -1) {
        return 1;
    }

    pid1 = fork();
    if (pid1 == -1) {
        return 1;
    } else if (!pid1) {
        pid1 = fork();
        if (pid1 == -1) {
            return 1;
        } else if (!pid1) {
            fd = open(argv[4], O_RDONLY);
            if (fd == -1) {
                _exit(1);
            }
            close(fds[0]);
            dup2(fd, 0);
            close(fd);
            dup2(fds[1], 1);
            close(fds[1]);
            execlp(argv[1], argv[1], NULL);
            _exit(1);
        }

        close(fds[0]);
        dup2(fds[1], 1);
        close(fds[1]);
        waitpid(pid1, &status, 0);
        if (WIFEXITED(status) && !WEXITSTATUS(status)) {
            execlp(argv[2], argv[2], NULL);
            _exit(1);
        }
    }

    pid = fork();
    if (pid == -1) {
        return 1;
    } else if (!pid) {
        fd = open(argv[5], O_CREAT | O_WRONLY | O_APPEND, 0777);
        if (fd == -1) {
            _exit(1);
        }
        dup2(fds[0], 0);
        dup2(fd, 1);
        close(fds[0]);
        close(fds[1]);
        close(fd);
        execlp(argv[3], argv[3], NULL);
        _exit(1);
    }

    close(fds[0]);
    close(fds[1]);
    waitpid(pid, NULL, 0);
    waitpid(pid1, NULL, 0);
    return 0;
}