1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;

ll n;
ll coins[202000];

int main() {
  cin >> n;
  
  
  ll max_a = 0;
  for (int i = 0; i < n; i++) {
    ll a;
    cin >> a;
    coins[a]++;
    max_a = max(max_a, a);
  }
  
  // cout << max_a << "\n";
  
  ll ans = 0;
  for (int i = 0; (i <= max_a) || (coins[i] != 0); i++) {
    // cout << i << " " << coins[i] << "\n";
    if (coins[i] != 0) {
      ans = i;
    }
    coins[i + 1] += coins[i] / 2;
  }
  
  cout << ans << "\n";
  
  return 0;
}