#include <stdio.h>

main()
{
	int n; /* upper limit */
	int i;

	/* Read n */
	printf("Input n: ");
	scanf("%d", &n);

	/* Output all prime numbers <= n */
	printf("Prime numbers <= n are:\n");
	for (i = 2; i <= n; i++)
		if (is_prime(i)) /* n prime */
			printf("%d ", i);
	printf("\n");
}


/* Checks if number m is prime */
int is_prime(int m)
{
	int i;

	for (i = 2; i < m; i++)
		if (m % i == 0) /* m composite */
			return 0;
	m = 0;
	return 1; /* m prime */
}