#include <bits/stdc++.h>
using namespace std;
int INF = 1000000;
int main(){
  long long A;
  cin >> A;
  A--;
  long long ans = INF;
  for (int i = 2; i < 100; i++){
    long long B = A;
    long long tmp = 0;
    while (B > 0){
      B /= i;
      tmp += i;
    }
    ans = min(ans, tmp);
  }
  for (int i = 1; i <= 100; i++){
    long long tmp = pow(A, (double) 1 / i);
    tmp = max(tmp - 2, (long long) 0);
    while (1){
      long long tmp2 = 1;
      for (int j = 0; j < i; j++){
        tmp2 *= tmp;
      }
      if (tmp2 < A){
        tmp++;
      } else {
        break;
      }
    }
    ans = min(ans, tmp * i);
  }
  cout << ans << endl;
}