#include<stdio.h>
#include<string.h>

int sieve(int a[],int n)
{
    int position,temp,i;
    a[1]=1;
    for(position=3; position*position<=n; position=position+2)
    {
        for(temp=position; temp*position<=n; temp=temp+2)
        {
            a[temp*position]=1;
        }
    }
    for(i=4; i<=n; i=i+2) a[i]=1;
    return 0;
}



int main()
{
    int n;
    scanf("%d",&n);

    int prime[n+1]= {0},position,temp,i,j;
    int sum[n+1]= {0};
    int index[n];
    for(i=1; i<=n; i++) index[i]=i;

    sieve(prime,n);

    //build up of sum array
    for(i=1; i<=n; i++)
    {
        if(prime[i]==0) //if the target index is prime
        {
            for(j=1; j<=i; j++)
            {
                if(prime[j]==1||j==i)
                    sum[i]=sum[i]+index[j];
                else
                    sum[i]=sum[i]+sum[j];
            }

        }
        else  //if the target string is not prime
        {
            sum[i]=index[i];
        }

    }


    int total=0;
    for(i=1; i<n; i++)
    {
        total=total+sum[i];
    }

    printf("%d\n",total+n);
    return 0;
}