/**
 *  author:   TakeruOkuyama
 *  created:  2020-04-09 14:53:46
**/
#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>;

const int MOD = 1000000007;

int main(){
    int N;
    cin >> N;
    ll sum = 0;
    rep(i, N){
        if((i+1)%3!=0&&(i+1)%5!=0){
            sum += i+1;
        }
    }
    cout << sum << endl;
return 0;}

/**
 * g++ code.cpp
 * ./a.out
 * shift + ctrl + i
**/ 