#include<bits/stdc++.h>
#define rep(i,a,b) for(int i=a;i<=(b);++i)
#define mem(a,x) memset(a,x,sizeof(a))
#define pb push_back
#define pi pair<int, int>
#define mk make_pair
using namespace std;
typedef long long ll;
int main()
{
    int n;
    cin>>n;
    ll ans=0;
    for(int i=1;i<=n;++i){
        if(i%3==0||i%5==0) continue;
        ans+=i;
    }
    cout<<ans<<endl;
}
