#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); ++i)
using namespace std;
using ll = long long;
using P = pair<int,int>;
#define chmax(x,y) x = max(x,y)
#define chmin(x,y) x = min(x,y)

int main() {
ios::sync_with_stdio(false);
cin.tie(0);

int n;
cin>>n;

ll ans=0;
for(int i=1;i<=n;i++)
{
    if(i%3!=0&&i%5!=0)ans+=i;
}
cout<<ans<<endl;
return 0;
}
