#include <iostream>
#include <bits/stdc++.h>
using namespace std;
int a[10000010];
int n,m,l = 0, r = 1e9;
long long sum = 0;
bool check( int h )
{
long long sum = 0;
for ( int i = 1;i <= n;i++ )
{
if ( a[i] > h )
{
sum += a[i] - h;
}
}
return sum >= m;
}
int main()
{
cin >> n >> m;
for ( int i = 1;i <= n;i++ )
{
cin >> a[i];
}
while ( l <= r )
{
int m = ( l + r ) / 2;
if ( check(m) )
{
sum = m;
l = m + 1;
}
else
{
r = m - 1;
}
}
cout << sum;
}
//未经授权，静止更改、抄袭。
