#include<bits/stdc++.h>
using namespace std;
#define ll long long

int n;
ll ans;

int main()
{
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
    {
        if(i%3!=0&&i%5!=0) ans+=i;
    }
    printf("%lld\n",ans);
    return 0;
}