semaphore mutex = 1;
semaphore odd_count = 0;
semaphore even_count = 0;
void P1() {
    while (true) {
        int item = produce();
        wait(mutex);
        put(item);
        if (item % 2 == 0) {
            signal(even_count);
        } else {
            signal(odd_count);
        }
        signal(mutex);
    }
}
void P2() {
    while (true) {
        wait(odd_count);
        wait(mutex);
        int item = getodd();
        countodd(item);
        signal(mutex);
    }
}
void P3() {
    while (true) {
        wait(even_count);
        wait(mutex);
        int item = geteven();
        counteven(item);
        signal(mutex);
    }
}
void wait(semaphore s) {}
void signal(semaphore s) {}