#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int,int> P;

#define p_ary(ary,a,b) do { cout << "["; for (int count = (a);count < (b);++count) cout << ary[count] << ((b)-1 == count ? "" : ", "); cout << "]\n"; } while(0)
#define p_map(map,it) do {cout << "{";for (auto (it) = map.begin();;++(it)) {if ((it) == map.end()) {cout << "}\n";break;}else cout << "" << (it)->first << "=>" << (it)->second << ", ";}}while(0)

template<typename T1,typename T2>ostream& operator<<(ostream& os,const pair<T1,T2>& a) {os << "(" << a.first << ", " << a.second << ")";return os;}

const char newl = '\n';

int main() {
    ll a;
    cin >> a;
    ll ans = 1e18;
    for (int i = 1;i < 61;++i) {
        ll ng = 1,ok = 1e18;
        while (abs(ok-ng) > 1) {
            ll mid = (ok+ng)/2,d = 1;
            bool f = false;
            for (int j = 0;j < i;++j) {
                if (d >= INT64_MAX/mid) f = true;
                d *= mid;
            }
            if (d >= a) f = true;
            (f ? ok : ng) = mid;
        }
        ans = min(ans,i*ok);
    }
    cout << ans << endl;
}