#include <bits/stdc++.h>
using namespace std;
 
#define fi first
#define se second
#define pb push_back
using vi = vector <int>;
using ll = long long;
using pii = pair <int, int>;
//~ const ll mod = 998244353;
const ll mod = 1e9 + 7;
ll qpow(ll a, ll b, ll m = mod) { ll r = 1, t = a;
	for(; b; b /= 2) { if(b & 1) r = r * t % m; t = t * t % m; } return r; }

using ld = long double;

int main() {
	ios :: sync_with_stdio(false);
	
	ld a; cin >> a;
	
	ld ans = 1e18;
	for(ld b = 2; b <= 100; b ++) {
		ld c = 0, t = 1;
		while(t < a) {
			t *= b;
			c ++;
		}
		
		ans = min(ans, c * b);
	}
	
	cout << ll(ans) << '\n';
}