#include <unistd.h>
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <limits.h>
#include <signal.h>

volatile __sig_atomic_t flag = 0;

void handler(int s)
{
    flag = 1;
}

int main(int argc, char *argv[])
{
    setbuf(stdin, NULL);
    sigaction(SIGUSR1, &(struct sigaction) {.sa_handler=handler, .sa_flags=SA_RESTART}, NULL);

    pid_t proc1 = getpid();
    long long int mul;
    long long int tmp;

    sscanf(argv[1], "%lld", &mul);

    int fd[2];
    pipe(fd);

    pid_t proc2;
    if ((proc2 = fork()) == 0) {
        proc2 = getpid();
        pid_t proc3;
        if ((proc3 = fork()) == 0) {
            while (1) {
                while (flag == 0) {
                    pause();
                }
                flag = 0;
                read(fd[0], &tmp, sizeof(tmp));
                tmp *= mul;
                write(fd[1], &tmp, sizeof(tmp));
                kill(proc1, SIGUSR1);
            }
        }
        flag = 1;
        while (scanf("%lld", &tmp) != EOF) {
            while (flag == 0) {
                pause();
            }
            flag = 0;
            write(fd[1], &tmp, sizeof(tmp));
            kill(proc3, SIGUSR1);
        }
        kill(proc1, SIGINT);
        kill(proc3, SIGINT);
        exit(0);
    }
    while (1) {
        while (flag == 0) {
            pause();
        }
        read(fd[0], &tmp, sizeof(tmp));
        printf("%lld\n", tmp);
        fflush(stdout);
        flag = 0;
        kill(proc2, SIGUSR1);
    }
}