#include <iostream>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <cmath>
#include <queue>
#include <numeric>
#include <bitset>

using namespace std;
#define repp(i,a,b) for(int i = (int)(a) ; i < (int)(b) ; ++i)
#define reppe(i,a,b) for(int i = (int)(a) ; i <= (int)(b) ; ++i)
#define repm(i,a,b) for(int i = (int)(a) ; i > (int)(b) ; --i)
#define repme(i,a,b) for(int i = (int)(a) ; i >= (int)(b) ; --i)

typedef long long ll;

long long GCD(long long a, long long b){if(b==0)return a;return GCD(b,a%b);}

int main() {
    int N; cin >> N;

    long long res = 0;
    repp(i,1,N) {
        if (i % 3 != 0 && i % 5 != 0) res += i;
    }
    cout << res << endl;
}
