#include<stdio.h>
long a[1000001];
long long i,j,s,n;
  
int main(){
	FILE *fin;
	fin=fopen("fractii.in","rt");
    fscanf(fin,"%lld",&n);
    for(i=1;i<=n;i++){
		a[i]=i-1;
    }
    for(i=2;i<=n;i++){
        for(j=2*i;j<=n;j=j+i){
            a[j]=a[j]-a[i];
        }
    }
    for(i=2;i<=n;i++){
        s=s+a[i];
    }
	FILE *fout;
	fout=fopen("fractii.out","wt");
    fprintf(fout,"%lld\n", 2*s+1);
    return 0;
}