#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
using ll = long long;

int main() {
	int N;cin >> N;
	vector<ll> H(N);
	for (int i = 0;i < N;i++) cin >> H[i];
	ll ng = -1;
	ll ok = 1e7;
	sort(H.begin(),H.end());
	while (ok-ng > 1) {
		ll mid = (ok + ng) / 2;
		vector<ll> now = H;
		ll K = mid;
		while (K >= 0 and !now.empty()) {
			if (K >= 60) {
				now.pop_back();
			} else {
				sort(now.begin(),now.end());
				if (now.back() <= (1LL << K)) {
					now.pop_back();
				} else {
					now.back() -= (1LL << K);
				}
			}
			K--;
		}
		if (now.empty()) {
			ok = mid;
		} else {
			ng = mid;
		}
	}
	cout << ok + 1 << endl;
}