#include <iostream>
#include <string>
#include <sstream>
#include <stack>
#include <algorithm>
#include <cmath>
#include <queue>
#include <bitset>
#include <iomanip>
#include <limits>
#include <chrono>
#include <random>
#include <array>
#include <unordered_map>
#include <functional>
#include <complex>
#include <numeric>
#include <cctype>
#include <map>
#include <set>
#include <cstdlib>
#include <bitset>
#include <tuple>
#include <assert.h>
#include <deque>


template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

constexpr long long INF = 1LL << 60;
constexpr int inf = 1000000007;
constexpr long long mod = 1000000007LL;
//constexpr long long mod = 998244353LL;

using namespace std;
typedef long long ll;


ll power(ll x, ll n) {
	if (n == 0) {
		return 1;
	}
	if (n % 2 == 0) {
		return power(x * x, n / 2);
	}
	else {
		return x * power(x, n - 1);
	}
}

ll f(ll X, ll c) {
	ll t = pow(X, 1.0 / (double)c);
	ll res = INF;
	for (ll i = max(0LL, t - 2); i <= t + 2; i++) {
		if (power(i, c) >= X) {
			chmin(res, i);
		}
	}
	return res;
}

int main()
{

	cin.tie(nullptr);
	ios::sync_with_stdio(false);

	ll a; cin >> a;
	ll res = INF;
	for (ll i = 1; i <= 60; i++) {
		chmin(res, i * f(a, i));
	}
	cout << res << endl;
}