#include<bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n) for (int i=0;i<(n);i++)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
typedef long long LL;
int N;

int main(){
	cin>>N;
	LL ans=0;
	REP(i,N){
		if((i+1)%3==0||(i+1)%5==0)continue;
		ans+=(i+1);
	}
	cout<<ans<<endl;
}