#include<stdio.h>
int main()
{long n,i,a,j,k,r,x,p,v[1000],ok;
FILE *f=fopen("fractii.in","r");
FILE *g=fopen("fractii.out","w");
fscanf(f,"%ld",&n);
k=2*n-1;
for (i=2; i<=n; i++)
		{
		x=i; p=0; a=2;
		 while (x!=1)
			 { if (x%a==0){p++; v[p]=a;}
				while (x%a==0) x=x/a;
				 a++;}
		 if (p==1&&v[1]==i&&i!=2) k=k+n-1;
		 else
			for (j=2; j<=n; j++)
				{ok=1;
				for (r=1;r<=p;r++&&ok==1)
					if (j%v[r]==0) ok=0;
				if (ok==1) k++;}
		}
fprintf(g,"%ld",k);
 fclose(f);
 fclose(g);
 return 0;  }