#include<bits/stdc++.h>

using namespace std;
using ll=long long;
#define rep2(i, a, n) for(int i = (a); i < (n); i++)
#define rep(i, n) rep2(i,0,n)

template<class T>
inline bool chmin(T& a, T b){if(a>b){a=b;return true;} return false;}

int main(){
  cin.tie(nullptr);ios_base::sync_with_stdio(false);
  ll n;cin>>n;
  int ans=10000;
  rep2(i,1,100){
    rep2(j,1,100){
      if(n<=pow(i,j)){
        chmin(ans,i*j);
      }
    }
  }
  cout<<ans<<endl;
}