//12/04/2020
#include<bits/stdc++.h>
#include<cmath>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

#define debug printf("Debug\n");
#define en '\n'


#define ll long long
#define ull unsigned long long

#define pi acos(-1.0)
#define mod 1000000007

#define _fastio  ios_base:: sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define in_fre  freopen("in.txt", "r", stdin);
#define out_fre freopen("out.txt", "w", stdout);

struct Node{
    ll val,pos;
};
struct OverloadedNode{
    ll val,pos;
    bool operator < (const OverloadedNode &rhs) const {
        if(val==rhs.val) return pos<rhs.pos;
        else return val<rhs.val;
    }
};
//Algos
template<typename T> using Pbds=tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
//typedef tree<OverloadedNode,null_type,less<OverloadedNode>,rb_tree_tag,tree_order_statistics_node_update>OverloadedPbds;

//Number Theory
template <typename T> T BigMod (T b,T p,T m){if (p == 0) return 1;if (p%2 == 0){T s = BigMod(b,p/2,m);return ((s%m)*(s%m))%m;}return ((b%m)*(BigMod(b,p-1,m)%m))%m;}
template <typename T> T ModInv (T b,T m){return BigMod(b,m-2,m);}
template <typename T> T gcd(T a,T b){if(a<0)return gcd(-a,b);if(b<0)return gcd(a,-b);return (b==0)?a:gcd(b,a%b);}
template <typename T> T lcm(T a,T b) {if(a<0)return lcm(-a,b);if(b<0)return lcm(a,-b);return a*(b/gcd(a,b));}

//Geometry
template <typename T> T Dis(T x1,T y1,T x2, T y2){return sqrt( SQR(x1-x2) + SQR(y1-y2) );}
template <typename T> T Angle(T x1,T y1,T x2, T y2){ return atan2( double(y1-y2) , double(x1-x2));}


/*Containers*/
//vector<ll>v;
//deque<ll>dq;
//stack<ll>stk;
//map<ll,ll>mp;
//unordered_map<ll,ll>ump;
//set<ll>st;
//multiset<ll>mst;
//unordered_set<ll>ust;
//unordered_multiset<ll>umst;
//priority_queue<ll,deque<ll>,greater<ll>>pq;
//Pbds<ll>ost;
/*OverLoaded Containers*/
//vector<OverloadedNode>v;
//deque<OverloadedNode>dq;
//stack<OverloadedNode>stk;
//map<OverloadedNode,OverloadedNode>mp;
//set<OverloadedNode>st;
//multiset<OverloadedNode>mst;
//priority_queue<OverloadedNode>pq;
//OverloadedPbds oost;
/*Global Variables*/

int main(){
    _fastio
    ll n;
    cin>>n;
    ll ans=(n*(n+1))/2;
    ll x=n/3;
    x=(x*(x+1))/2;
    ans-=(x*3);
    x=n/5;
    x=(x*(x+1))/2;
    ans-=(x*5);
    x=n/15;
    x=(x*(x+1))/2;
    ans+=(x*15);
    cout<<ans<<en;



    return 0;
}
