#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#include <utility>
#include <functional>
#include <time.h>
#include <stack>
#include <array>
#define popcount __builtin_popcount
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;
using lll=__int128_t;

int main()
{
    ll a; cin>>a;
    ll ans=a;
    for(int m=2; m<=60; m++){
        ll l=1, r=1e9+7;
        while(r-l>1){
            ll mid=(l+r)/2;
            lll p=1;
            for(int i=0; i<m; i++){
                p*=mid;
                if(p>=a) break;
            }
            if(p>=a) r=mid;
            else l=mid;
        }
        ans=min(ans, r*m);
    }
    cout<<ans<<endl;
    return 0;
}