sasassas

#include<bits/stdc++.h>
using namespace std;
int n,s[110];
bool f()
{
	for (int i = 1;i < n;i++)
		if (s[i] != s[i - 1])
			return false;
	return true;
}
int main()
{
		cin>>n;
		for (int i = 0;i < n;i++)
			cin >> s[i];
		if (f())
			cout << 0 << endl;
		else
		{
			int t = 0;
			while (!f())
			{
				int w = s[0];
				for (int i = 0;i < n - 1;i++)
				{
					s[i] = s[i]+s[i + 1] / 2;
					s[i + 1] = s[i + 1] / 2;
				}	
				s[n - 1] += w / 2;
				s[0] -= w / 2;
				for (int i = 0;i < n;i++)
					if (s[i] % 2 == 1)
					{
						t++;
						s[i] += 1;
					}
			}
			cout << t << endl;
		}
	
	return 0;
}