#pragma GCC optimize ("O2")
#pragma GCC target ("avx2")
#include<bits/stdc++.h>

using namespace std;
typedef long long ll;
#define rep(i, n) for(int i = 0; i < (n); i++)
#define rep1(i, n) for(int i = 1; i <= (n); i++)
#define co(x) cout << (x) << "\n"
#define cosp(x) cout << (x) << " "
#define ce(x) cerr << (x) << "\n"
#define cesp(x) cerr << (x) << " "
#define pb push_back
#define mp make_pair
#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)
#define Would
#define you
#define please

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);


	ll A;
	cin >> A;
	ll saishou = 1000000;
	for (ll i = 2; i < 8; i++) {
		ll tmp = 1;
		ll kazu = 0;
		while (tmp < A) {
			tmp *= i;
			kazu++;
		}
		chmin(saishou, i * kazu);
	}

	co(saishou);

	Would you please return 0;
}