#include<stdio.h>
int cmmdc(int a,int b)
{int r;
while (b!=0)
{r=a%b;
a=b;
b=r;}
return a;
}
int main()
{freopen("fractii.in","r",stdin);
 freopen("fractii.out","w",stdout);
 long long n,i,j,c;
 scanf("%lld",&n);
 c=0;
 for(i=1;i<=n;i++) for(j=1;j<=n;j++){if((i==j+1)||(i==j-1))c++;
 												 else if(cmmdc(i,j)==1) c++;}
 printf("%lld",c);
 return 0;
}