#include <bits/stdc++.h>
using namespace std;

int main()
{
	long long A;
	cin >> A;

	long long ans = 0;
	long long mul = 1;
	long long n = 0;
	while( mul < A ) {
		mul *= 2;
		n++;
	}
	ans = n * 2;
	for( long long i = 3; i <= ans; i++ ) {
		mul = 1;
		n = 0;
		while( mul < A ) {
			mul *= i;
			n++;
		}
		ans = min( ans, n * i );
	}

	cout << ans << endl;
}