#include<stdio.h>
int n,x,y=4;
int main()
{
	int i=2,suma=0;
	bool ok=true;
	freopen("sum.in","r",stdin);
	freopen("sum.out","w",stdout);
	scanf("%d%d",&n,&x);
	while(y<=2*x)
	{
		
		for(i=2;i<=y/2 && ok!=false;++i)
		{
			if(y%x==0 && y%i!=0)
				ok=true;
			else ok=false;
		}
		if(y==2*x)
		{
			printf("%d\n",suma);
			scanf("%d",&x);
			suma=0;
		}
		if(ok==true)
			suma=suma+y;
		++y;
		ok=true;
	}
	return 0;
}