#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<iomanip>
#include<math.h>
#include<complex>
#include<queue>
#include<deque>
#include<stack>
#include<map>
#include<set>
#include<bitset>
#include<functional>
#include<assert.h>
#include<numeric>
using namespace std;
#define REP(i,m,n) for(int i=(int)(m) ; i < (int) (n) ; ++i )
#define rep(i,n) REP(i,0,n)
using ll = long long;
const int inf = 1e9 + 7;

int main() {
	long long int n, ans = 0;
	cin >> n;
	REP(i, 1, n) {
		if (i % 3 != 0 && i % 5 != 0)ans = ans + i;
	}
	cout << ans;
	return 0;


}