#include <iostream>
#include <algorithm>
#include <vector>
#include <cstdio>
#include <queue>
#include <deque>
using namespace std;
const int N=1000006;
struct ban
{
int l,r,x;
};
int n;
long long k;
int a[N],ll[N],rr[N];
long long b[N];
deque<ban> q;
int mm(int i)
{
if(i==1)
return n;
return i-1;
}
int pp(int i)
{
if(i==n)
return 1;
return i+1;
}
int main()
{
//freopen("g.in","r",stdin);
//freopen("g.out","w",stdout);
ios_base::sync_with_stdio(false);
cin>>n>>k;
for(int i=1;i<=n;++i)
cin>>a[i];
///////////////////////////////
for(int i=1;i<=n;++i)
{
ban t;
t.x=a[i];
t.l=i;
for(;a[i]==t.x && i<=n;++i)
t.r=i;
--i;
ll[t.r]=t.l;
rr[t.l]=t.r;
q.push_back(t);
}
if(a[1]==a[n])
{
ban t1=q.front(),t2=q.back();
q.pop_back();
q.pop_front();
ban t;
t.x=a[1];
t.l=t2.l;
t.r=t1.r;
ll[t.r]=t.l;
rr[t.l]=t.r;
q.push_back(t);
}
while(!q.empty())
{
ban t=q.front();
q.pop_front();
int l=t.l;
int r=t.r;
int x=t.x;
ban h;
if(l<=r)
{
if(!(a[l]<a[mm(l)] && a[r]<a[pp(r)]))
continue;
h.x=min(a[mm(l)],a[pp(r)]);
b[r-l+1]+=(h.x-x);
}
else
{
if(!(a[l]<a[mm(l)] && a[r]<a[pp(r)]))
continue;
h.x=min(a[mm(l)],a[pp(r)]);
b[r+n-l+1]+=(h.x-x);
}
h.l=l;
h.r=r;
if(h.x==a[mm(l)])
{
h.l=ll[mm(l)];
}
if(h.x==a[pp(r)])
{
h.r=rr[pp(r)];
}
ll[h.r]=h.l;
rr[h.l]=h.r;
q.push_front(h);
}
long long ans=0;
for(int i=1;i<=n;++i)
{
long long x=(i*b[i]);
if(k>=x)
{
k-=x;
ans+=b[i];
}
else
{
ans+=(k/i);
k=0;
break;
}
}
cout<<ans*2<<endl;
return 0;
}
