#include<iostream>
#include<vector>
#include<string>

using namespace std;

int main()
{
    int n;cin>>n;
    long long int sum=0;
    for(int i=1;i<=n;++i){
        if(i%3==0||i%5==0)continue;
        sum+=i;
    }
    cout<<sum<<endl;
    return 0;
}
