#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (int)(n); i ++)
#define irep(i,n) for (int i = (int)(n) - 1;i >= 0;--i)
using namespace std;
using ll = long long;
using PL = pair<ll,ll>;
using P = pair<int,int>;
constexpr int INF = 1000000000;
constexpr long long HINF = 100000'00000'00000'000;
constexpr long long MOD = 1000000007;// = 998244353;
constexpr double EPS = 1e-4;
constexpr double PI = 3.14159265358979;

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    ll A; cin >> A;
    auto solve = [&](ll n,ll m) {
        ll now = 1;
        rep(i,m) {
            if (now >= HINF/n) return true;
            now *= n;
        }
        return now >= A;
    };
    for (int x = 1; x <= 1000; ++x) {
        for (int i = 1;i*i <= x; ++i) {
            if (x%i == 0) {
                ll n = i,m = x/i;
                if (solve(n,m) || solve(m,n)) {
                    cout << n*m << '\n';
                    return 0;
                }
            }
        }
    }
    return 0;
}