#include<cstdio>
using namespace std;

const int DD = 1000001;
int v[DD];

int main (){
    FILE *in = fopen ("fractii.in","r");
    FILE *out = fopen ("fractii.out","w");

    int n; fscanf(in,"%d",&n);

    for(int i = 0 ; i <= n ; ++i)   v[i]=i-1;

    long long nr=0;
    for(int i = 1 ; i <= n ; ++i){
        for(int j = 2*i ; j <=n ; j+=i)
            v[j]-=v[i];
        nr+=v[i];
    }

    fprintf(out,"%d\n",2*nr+1);
    fclose(in);
    fclose(out);
    return 0;
}