#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <cmath>
#include <map>
#include <queue>
#include <iomanip>
#include <set>
#include <tuple>
#define mkp make_pair
#define mkt make_tuple
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define all(v) v.begin(),v.end()
using namespace std;
typedef long long ll;
const ll MOD=1e9+7;
template<class T> void chmin(T &a,const T &b){if(a>b) a=b;}
template<class T> void chmax(T &a,const T &b){if(a<b) a=b;}

const ll L=1e5;
const ll INF=2e18;

int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);

  ll A;
  cin>>A;

  ll ans=A;
  for(ll x=2;x<=min(A,L);x++){
    int num=0;
    ll val=1;
    while(val<A){
      if(val>INF/x){
        num=L;
        break;
      }
      val*=x;
      num++;
    }
    chmin(ans,num*x);
  }
  cout<<ans<<endl;

  return 0;
}