#define MAX 10000005
p[MAX];
four[1000];

int main(void)
{
  int i,j,f=0;

  for(i=2;i<MAX;i++)
    if(~p[i])
      for(j=i*2;j<MAX;j+=i)
	p[j] = 1;   
  for(i=3;i<MAX-7;i+=2)
    if(!(p[i]||p[i+2]||p[i+6]||p[i+8]))
      four[f++]=i+8;
  for(four[f]=MAX;scanf("%d",&j),j;printf("%d\n",four[i-1]))  
    for(i=0;four[i]<=j;i++);
  exit(0);
}