#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 (ll i = 2;;++i) {
        ll d = 1;
        int cnt = 0;
        while (d < a) {
            cnt++;
            d *= i;
        }
        ans = min(ans,cnt*i);
        if (i*i >= a) break;
    }
    cout << ans << endl;
}