#include <bits/stdc++.h>
using namespace std;
const int mx = 1e6 + 5;
int n, k, A[mx], ans; vector<int> range[mx]; vector<int> stk;
int main(){
cin >> n >> k;
for (int i = 1; i <= n; i++){
cin >> A[i];
while (!stk.empty() and A[stk.back()] <= A[i]) stk.pop_back();
stk.push_back(i);
}
for (int i = 1; i <= n; i++){
int mxTop = 0;
while (!stk.empty()){
int L = stk.back();
if (L < i) range[i - L - 1].push_back(min(A[L], A[i]) - mxTop);
else range[n - (L - i + 1)].push_back(min(A[L], A[i]) - mxTop);
if (A[L] > A[i]) break;
mxTop = max(mxTop, A[L]); stk.pop_back();
}
stk.push_back(i);
}
for (long long len = 1; len <= n; len++){
for (int lim : range[len]){
if (len * lim >= k) ans += 2 * (k / len), k = 0;
else ans += 2 * lim, k -= len * lim;
}
}
cout<<ans<<endl;
}
