#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <cmath>
#include <stdio.h>
#include <queue>
#include <deque>
#include <cstdio>
#include <set>
#include <map>
#include <bitset>
#include <stack>
#include <cctype>
using namespace std;
int main() {
	long long a;
	cin >> a;
	long long m = 1000000007;
	for (long long i = 2; i <= 100; i++) {
		long long ans = 1;
		int co = 0;
		while (ans < a) {
			ans *= i;
			co++;
		}
		if (co * i < m) {
			m = co * i;
		}
	}
	cout << m << endl;
	return 0;
}