#include <stdio.h>
#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000005
#define Inf64 1000000000000000001LL
int main(){
	
	int n;
	cin>>n;
	vector<long long> h(n);
	rep(i,n)cin>>h[i];
	
	long long ok = n + 70,ng = 0;
	while(ok-ng>1LL){
		long long mid = (ok+ng)/2;
		long long c = mid;
		priority_queue<long long> q;
		rep(i,n)q.push(h[i]);
		while(c>0 && q.size()>0){
			c--;
			long long t = q.top();
			q.pop();
			if(c > 61){
				continue;
			}
			if(t <= 1LL<<c)continue;
			q.push(t - (1LL<<c));
		}
		if(q.size()>0)ng = mid;
		else ok = mid;
	}
	cout<<ok<<endl;
	return 0;
}