#include "stdio.h"

int main()
{
    int N;
    scanf("%d", &N);
    long sum = 0;
    for (long i = 1; i < N + 1; i++)
    {
        if (i % 3 == 0 || i % 5 == 0)
        {
            continue;
        }
        sum += i;
    }
    printf("%ld\n", sum);
}