#include<cstdio>
const int N = 100000 + 5;
typedef long long ll;

int n;
ll c, arr[N];

int can(ll level)
{
	ll sum = 0;
	for(int i=0; i<n; ++i)
	{
		if(arr[i] < level)
		{
			sum += (level-arr[i])*(level-arr[i]);
			if(sum>c)
			{
				return 0;
			}
		}
	}
	if(sum <= c)
	{
		return 1;
	}
	return 0;
}

int main()
{
	ll x=1, y=20000000, mid, ans=0;
	
	scanf("%d%lld", &n, &c);
	for(int i=0; i<n; ++i)
	{
		scanf("%lld", &arr[i]);
	}
	
	while(x<=y)
	{
		mid = (x+y) / 2;
		if(can(mid))
		{
			x = mid+1;
			if(ans < x) ans = mid;
		}
		else
		{
			y = mid-1;
		}
	}
	
	printf("%lld\n", ans);
	
	return 0;
}