#include <bits/stdc++.h>
using namespace std;
const int mx = 1e6 + 5;
int n, k, A[mx], ans; priority_queue<pair<int, int>> pq; stack<int> stk;
int main(){
cin >> n >> k;
for (int i = 1; i <= n; i++){
cin >> A[i];
while (!stk.empty() and A[stk.top()] <= A[i]) stk.pop();
stk.push(i);
}
for (int i = 1; i <= n; i++){
int mxTop = 0;
while (!stk.empty()){
int L = stk.top();
int dst = (L < i) ? (i - L - 1) : (n - (L - i + 1));
if (dst) pq.push({-dst, min(A[L], A[i]) - mxTop});
if (A[L] > A[i]) break;
mxTop = max(mxTop, A[L]); stk.pop();
}
stk.push(i);
}
while (!pq.empty()){
pair<int, int> cur = pq.top(); pq.pop();
int use = min(k / -cur.first, cur.second);
ans += 2 * use; k -= use * -cur.first;
}
cout<<ans<<endl;
}
