#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>

void *hello_world(void *data) {
    printf("Hello World from thread %d\n", (int) data);
}

int main() {
    int i, n;
    pthread_t *threads;

    scanf("%d", &n);
    threads = (pthread_t*) malloc(n * sizeof(pthread_t));

    for (i = 0; i < n; i++) {
        pthread_create(&threads[i], NULL, hello_world, (void*) i);
    }

    for (i = 0; i < n; i++) {
        pthread_join(threads[i], NULL);
    }

    free(threads);
    return 0;
}