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

ll powll (ll a,ll n){
    if(60<n)return 2e18;
    ll res = 1;
    for(ll i = 0;i<n;i++)res*=a;
    return res;
}
int main(){
    ll n; cin >> n;
    multiset<ll> h;
    for(ll i = 0;i<n;i++){
        ll v; cin >> v;
        h.insert(v);
    }
    auto solve = [&](ll x)-> bool {
        multiset<ll> hp(h.begin(),h.end());
        while(hp.size()){
            x--;
            if(x<0)return false;
            ll atk = powll(2,x);
            ll M = *hp.rbegin();
            hp.erase(prev(hp.end()));
            ll nhp = M - atk;
            if(nhp > 0){
                hp.insert(nhp);
            }
        }
        return true;
    };
    ll ok = 250000;
    ll ng = 0;
    while(ok - ng > 1){
        ll mid = midpoint(ng,ok);
        if(solve(mid))ok = mid;
        else ng = mid;
    }
    cout << ok << endl;
}