/* -*- coding: utf-8 -*-
 *
 * 3281.cc:  No.3281 Pacific White-sided Dolphin vs Monster - yukicoder
 */

#include<cstdio>
#include<queue>
#include<algorithm>

using namespace std;

/* constant */

const int MAX_N = 100000;
const int BN = 60;

/* typedef */

using ll = long long;

/* global variables */

ll hs[MAX_N];

/* subroutines */

bool check(int n, int x) {
  if (x > BN) n -= (x - BN), x = BN;
  if (n <= 0) return true;
  
  priority_queue<ll> q(hs, hs + n);
  for (int i = x - 1; ! q.empty() && i >= 0; i--) {
    ll bi = 1LL << i;
    auto h = q.top(); q.pop();
    if (h > bi) q.push(h - bi);
  }

  return q.empty();
}

/* main */

int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) scanf("%lld", hs + i);
  sort(hs, hs + n);

  int x0 = 0, x1 = n + BN;
  while (x0 + 1 < x1) {
    int x = (x0 + x1) / 2;
    bool f = check(n, x);
    //printf(" check(%d,%d)=%d\n", n, x, f);
    if (f) x1 = x;
    else x0 = x;
  }
  
  printf("%d\n", x1);
  
  return 0;
}