#define _USE_MATH_DEFINES
#include "bits/stdc++.h"
using namespace std;
#define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i))
#define rep(i,j) FOR(i,0,j)
#define each(x,y) for(auto &(x):(y))
#define mp make_pair
#define MT make_tuple
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<#x<<": "<<(x)<<endl
#define smax(x,y) (x)=max((x),(y))
#define smin(x,y) (x)=min((x),(y))
#define MEM(x,y) memset((x),(y),sizeof (x))
#define sz(x) (int)(x).size()
#define RT return
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;
using vll = vector<ll>;

vector<int> sieve(int n) {
    vector<bool> f(n + 1);
    for (int i = 3; i <= n; i += 2) f[i] = 1;
    for (int i = 3; i <= sqrt(n); i += 2) if (f[i]) for (int j = i * 3; j <= n; j += i) f[j] = 0;
    vector<int> res;
    if (n >= 2)res.push_back(2);
    for (int i = 3; i <= n; i += 2) if (f[i]) res.push_back(i);
    return res;
}

int MI = INT_MIN / 2;
// 35以下の素数11個

void solve() {
    int N, M = 0;
    cin >> N;
    auto p = sieve(N);
    while (p[M] * p[M] <= N)M++;

    vi cu(1 << M, -1), ne(1 << M);
    vi flag(N + 1), bigPrime(N + 1);
    for (int i = 2; i <= N; ++i) {
        int x = i;
        rep(j, M) {
            if (x%p[j] == 0)flag[i] |= 1 << j;
            while (x%p[j] == 0)x /= p[j];
        }
        bigPrime[i] = x;
    }

    cu[0] = 0;

    FOR(i, 2, N + 1){
        fill(all(ne), MI);
        rep(j, 1 << M) {
            auto z = cu[j];
            if (z < 0)continue;
            smax(ne[j], cu[j]);
            if (binary_search(p.begin() + M, p.end(), i)) {
                for (int k = 1; k*i <= N; ++k) {
                    int x = k * i;
                    if (!(flag[x] & j)) {
                        smax(ne[flag[x] | j], z + x);
                    }
                }
            } else if (bigPrime[i] == 1) {
                if (!(flag[i] & j)) {
                    smax(ne[flag[i] | j], z + i);
                }
            }
        }
        swap(cu, ne);
    }
    
    cout << cu.back() << endl;
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout << fixed << setprecision(15);
	solve();
	return 0;
}