#include <bits/stdc++.h>
using namespace std;
long long INF = 1000000000;
int main(){
  long long A;
  cin >> A;
  long long ans = INF;
  for (int i = 1; i <= 1000; 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;
      }
    }
    if (tmp > 1){
      ans = min(ans, tmp * i);
    }
  }
  cout << ans << endl;
}