#include <bits/stdc++.h>

using namespace std;

typedef long long int ll;

int main(){
    int t;
    cin>>t;
    ll sum = 0;
    for(int i = 1;i<= t;i++){
        if( i %3 == 0 || i% 5 == 0)continue;
        else sum+= i;
    }
    cout<<sum<<endl;
}