#include <stdio.h>    
long long n,i,j,a[1000000];    
int main()    
{    
FILE *in=fopen("fractii.in","rt"), *out=fopen("fractii.out","w+");    
fscanf(in,"%lld",&n);    
for (i=1; i<=n; ++i) a[i]=i-1;    
for (i=2; i<=n; ++i)    
for (j=i*2; j<=n; j+=i) a[j]-=a[i];    
for (i=0, j=0; i<=n; j+=a[i]) ++i;
fprintf(out,"%lld",j*2+1);    
return 0;    
}