#include <stdio.h>
#include <math.h>
#define maxl 100010

int i,j,n,m,k,cop,v,nr;
int ciur[maxl];
int divi[1010];
long long sol;

int main()
{
    freopen("fractii.in","r",stdin);
    freopen("fractii.out","w",stdout);
    
    scanf("%d",&n);
    for (i=1; i<=n; i++)
    {
        cop=i;m=0;
        if (cop%2==0)
        {
            divi[++m]=2;
            while (!(cop%2)) cop/=2;
        }
        while (cop>1)
        {
              k=(int)sqrt(cop);v=cop;
              for (j=3; j<=k; j+=2)
                  if (cop%j==0) 
                  {
                     divi[++m]=j;
                     while (!(cop%j)) cop/=j;
                  }
              if (cop==v)
              {
                 divi[++m]=cop;
                 cop=1;           
              }
        }        

    }
    printf("%lld\n",sol);
        
    return 0;    
}