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
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
#include<bits/stdc++.h>
#define rep(i,a,b) for(int i=a;i<b;i++)
#define per(i,a,b) for(int i=a;i>b;i--)
#define repLL(i,a,b) for(LL i=(LL)a;i<(LL)b;i++)
#define perLL(i,a,b) for(LL i=(LL)a;i>(LL)b;i--)
#define debug5(a,b,c,d,e) cerr<<#a<<": "<<a<<" "<<#b<<": "<<b<<" "<<#c<<": "<<c<<" "<<#d<<": "<<d<<" "<<#e<<": "<<e<<endl;
#define debug4(a,b,c,d)  cerr<<#a<<": "<<a<<" "<<#b<<": "<<b<<" "<<#c<<": "<<c<<" "<<#d<<": "<<d<<endl;
#define debug3(a,b,c) cerr<<#a<<": "<<a<<" "<<#b<<": "<<b<<" "<<#c<<": "<<c<<endl;
#define debug2(a,b) cerr<<#a<<": "<<a<<" "<<#b<<": "<<b<<endl;
#define debug(a) cerr<<#a<<": "<<a<<endl;
#define pb push_back
#define mp make_pair
#define SZ(x) ((int)(x).size())
#define ALL(x) x.begin(),x.end()
#define fi first
#define se second
#define _upgrade ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

using namespace std;

typedef long long LL;
typedef pair<int,int> PII;
typedef pair<LL,LL> PLL;
typedef vector<PII> VPII;
typedef vector<PLL> VPLL;
typedef vector<LL> VLL;
typedef vector<int> VI;
typedef vector<string> VS;
typedef vector<char> VC;
typedef long double LD;
typedef pair<LD,LD> PLD;
typedef vector<LD> VLD;
typedef vector<PLD> VPLD;

const int maxn=(1e6)+7;
const int inf=(1e9)+7;
const LL LLinf=(1e18)+7;
const LD eps=1e-9;
const LL mod=1e9+7;

// ***************************** CODE ***************************** //

int tab[maxn];

int main()
{
      _upgrade
      int n;
      cin>>n;
      rep(i,0,n)
      {
            int a;
            cin>>a;
            tab[a]++;
      }
      int res=0;
      rep(i,0,maxn-1)
      {
            if(tab[i]!=0)
                  res=i;
            tab[i+1]+=tab[i]/2;
      }
      cout<<res;
      return 0;
}