#include <cstdio>
#include <iostream>
#include <vector>
#include <string>
#include <algorithm>

using namespace std;

int main(void)
{
    int n;
    cin >>n;

    long long sum = 0;

    for(int i = 1; i <= n; i++){
        if(i % 3 == 0 || i % 5 == 0){
            continue;
        }
        sum += i;
    }

    printf("%lld\n", sum);
    return 0;
}