#include <stdio.h>
int main ()
{
	int q,p,j,i,total;
	p=1;
	q=1;
	total=0;
	printf("please press any number.");
	scanf("%d",&j);
	
	while(q<=j)
	{
		p=++p;
		i=0;
		while(i<p && (i==0 || i==1 || p%i!=0 ))
		{
			i=++i;
			if(p%i==0 && i==p)
			{
				q=++q;
				total=total+p;
			}
		}
	}
	printf("%d\n",total);
	return 0;
}