#include<iostream>
#include<map>

using namespace std;

using ll = long long;

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