/**
 *   @FileName	a.cpp
 *   @Author	kanpurin
 *   @Created	2020.08.21 21:38:20
**/

#include "bits/stdc++.h" 
using namespace std; 
typedef long long ll;


template<typename T, typename U>
T _pow(T k, U n, T unity = 1) {
    while (n > 0) {
        if (n & 1) {
            unity *= k;
        }
        k *= k;
        n >>= 1;
    }
    return unity;
}
int main() {
    ll a;cin >> a;
    ll ans = 1e18+1;
    for (int i = 1; i < 64; i++) {
        ll k = (ll)pow(a,1.0/i);
        if ((ll)_pow(k,i) >= a) {
            ans = min(ans,k*i);
        }
        else {
            ans = min(ans,(k+1)*i);
        }
        
    }
    cout << ans << endl;
    return 0;
}