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
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
#include <stdio.h>
#include <iostream>


using namespace std;


typedef long long unsigned int  llu;


static const int MAX_SIZE = 201718 + 30;


static llu aCnt[MAX_SIZE];


static void Init()
{
    for (int i = 0; i < MAX_SIZE; ++i)
    {
        aCnt[i] = 0;
    }
}


static void ReadData()
{
    int n, x;

    scanf("%d", &n);

    for (int i = 0; i < n; ++i)
    {
        scanf("%d", &x);

        aCnt[x]++;
    }
}


static void Solve()
{
    for (int i = 0; i < MAX_SIZE; ++i)
    {
        llu a = aCnt[i];

        aCnt[i] = 0;

        llu iMask = 1;
        int iOffset = 0;

        for (; a != 0; iMask <<= 1, ++iOffset)
        {
            if ((a & iMask) != 0)
            {
                aCnt[i + iOffset]++;

                a -= iMask;
            }
        }
    }
}


static void WriteResult()
{
    for (int i = MAX_SIZE - 1; i >= 0; --i)
    {
        if (aCnt[i] != 0)
        {
            printf("%d", i);
            break;
        }
    }
}


int main(int argc, char * argv[])
{
    Init();
    ReadData();
    Solve();
    WriteResult();

	return 0;
}