#include<cstdio>
using namespace std;
int rez,N,A[1000010];
int main()
{
    freopen("fractii.in","r",stdin);
    freopen("fractii.out","w",stdout);
    scanf("%d",&N);
    for (int i=1;i<=N;++i) A[i]=i;
    for (int i=2;i<=N;++i)
    {
        rez+=A[i];
        for (int j=i+1;j<=N;++j) A[j]-=A[i];
    }
    printf("%d\n",rez);
    fclose(stdin); fclose(stdout);
    return 0;
}