#include <bits/stdc++.h>
#define INF 2000000000000000000
#define ll long long
using namespace std;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  ll A;
  cin >> A;
  ll ans = INF;
  for (ll i = 1; i <= 60; ++i) {
    if (A <= pow(2, i)) {
      ans = i * 2;
      break;
    }
  }
  for (ll i = 1; i <= 38; ++i) {
    if (A <= pow(3, i)) {
      ans = min(ans, i * 3);
      break;
    }
  }
  for (ll i = 1; i <= 26; ++i) {
    if (A <= pow(5, i)) {
      ans = min(ans, i * 5);
      break;
    }
  }
  for (ll i = 1; i <= 22; ++i) {
    if (A <= pow(7, i)) {
      ans = min(ans, i * 7);
      break;
    }
  }
  cout << ans << "\n";
}