#include<iostream.h>
#include<stdio.h>
int main ()
{long int P,Q,N,contor=1,truth=1,truth2=3;
freopen ("fractii.in", "rt" ,stdin);
freopen ("fractii.out","wt" ,stdout);
cin>>N;
if (N==1) cout<<truth;
else if (N==2) cout<<truth2;
else {for (contor=2N-1,P=2;P<=N;P++)
          {Q=2;
           while (Q<N) {if (P%Q!=0) contor++;
                        Q++;}}
cout<<contor;}
return 0;}