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

#ifndef _WIN32
    #define getchar getchar_unlocked
#endif

#define MP make_pair
#define PB push_back
#define ST first
#define ND second

typedef long long int LLI;
typedef unsigned long long int LLU;
typedef long double LD;
typedef pair<int, int> pii;
typedef pair<long long int, long long int> pll;
typedef vector<int> vi;

template<class TH> void _dbg(const char *sdbg, TH h){cerr<<sdbg<<"="<<h<<"\n";}
template<class TH, class... TA> void _dbg(const char *sdbg, TH h, TA... a) {
  while(*sdbg!=',') cerr<<*sdbg++;
  cerr<<"="<<h<<",";
  _dbg(sdbg+1, a...);
}
#define debug(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
#define boost ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)

int kek[500007];

int32_t main()
{
	int n; scanf("%d", &n);
	for(int i = 1; i <= n; ++i){ int x; scanf("%d", &x); ++kek[x]; }
	int odp = 0;
	for(int i = 0; i < 500006; ++i){
		if(kek[i] > 0) odp = max(odp, i);
		kek[i + 1] += kek[i] / 2;
	}
	printf("%d", odp);
}