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
#include <bits/stdc++.h>
using namespace std;

typedef long long LL;
typedef long double LD;
typedef pair < int, int > PII;
typedef pair < LL, LL > PLL;
typedef pair < LD, LD > PDD;

#define _upgrade ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
template < typename _T > inline void _DBG(const char *s, _T x) { cerr << s << " = " << x << "\n"; }
template < typename _T, typename... args > void _DBG(const char *s, _T x, args... a) { while(*s != ',') cerr << *s++; cerr << " = " << x << ','; _DBG(s + 1, a...); }

#ifdef LOCAL
#define DBG(...) _DBG(#__VA_ARGS__, __VA_ARGS__)
#else
#define DBG(...) (__VA_ARGS__)
#define cerr if(0) cout
#endif

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

const int N = 3e5 + 7;

int T[N];

int main()
{
    int n; scanf("%d", &n);
    int mx = 0;
    for(int i = 0; i < n; i++)
    {
        int x; scanf("%d", &x);
        T[x]++;
        mx = max(mx, x);
    }
    int ans = 0;
    for(int i = 0; i < mx + 30; i++)
    {
        T[i + 1] += T[i] / 2;
        if(T[i] > 0) ans = i;
    }
    printf("%d\n", ans);
	return 0;
}