#include <cassert>
#include <vector>
#include <functional>

template <class T = long long, class Comp = std::less<T>>
class Li_Chao_tree
{
    struct line
    {
        T slop, icpt;
        line *lch = nullptr, *rch = nullptr;
        bool del = false;
        ~line() { if(del) delete this; }
        line *swap(line &rhs) { std::swap(slop, rhs.slop); std::swap(icpt, rhs.icpt); return this; }
        T eval(const T x) const { return slop * x + icpt; }
    }; // struct line

    T lower, upper, eps;
    Comp comp;
    line *root = nullptr;

    static line *alloc(line ln)
    {
        static size_t len = 1;
        static line *use = new line[1], *end = (use->del = true, use + 1);
        if(use == end)
        {
            use = new line[len <<= 1];
            end = use + len;
            use->del = true;
        }
        return use++->swap(ln);
    }

    // // insert a line for the interval [l, r).
    line *insert(line *const p, const T l, const T r, line ln)
    {
        if(!p) return alloc(ln);
        bool lcmp = comp(ln.eval(l), p->eval(l));
        bool rcmp = comp(ln.eval(r - eps), p->eval(r - eps));
        if(lcmp == rcmp) return lcmp ? p->swap(ln) : p;
        if(r - l <= eps) return p;
        T mid = (l + r) / 2;
        if(comp(ln.eval(mid), p->eval(mid)))
        {
            p->swap(ln);
            lcmp = !lcmp;
        }
        if(lcmp) p->lch = insert(p->lch, l, mid, ln);
        else p->rch = insert(p->rch, mid, r, ln);
        return p;
    }

    // // insert a segment for the interval [l, r).
    line *insert(line *const p, const T l, const T r, line ln, const T s, const T t)
    {
        if(t - eps < l or r - eps < s) return p;
        T mid = (l + r) / 2;
        if(l < s or t < r)
        {
            p->lch = insert(p->lch, l, mid, ln, s, t);
            p->rch = insert(p->rch, mid, r, ln, s, t);
            return p;
        }
        if(!p) return alloc(ln);
        bool lcmp = comp(ln.eval(l), p->eval(l));
        bool rcmp = comp(ln.eval(r - eps), p->eval(r - eps));
        if(lcmp == rcmp) return lcmp ? p->swap(ln) : p;
        if(r - l <= eps) return p;
        if(comp(ln.eval(mid), p->eval(mid)))
        {
            p->swap(ln);
            lcmp = !lcmp;
        }
        if(lcmp) p->lch = insert(p->lch, l, mid, ln, s, t);
        else p->rch = insert(p->rch, mid, r, ln, s, t);
        return p;
    }

public:
    // domain set to be the interval [lower, upper).
    Li_Chao_tree(const T lower, const T upper, const T eps = 1, Comp comp = Comp())
        : lower(lower), upper(upper), eps(eps), comp(comp) {}

    bool empty() const { return !root; }

    // insert a line whose slope is p and inception is q.
    void insert(const T p, const T q) { root = insert(root, lower, upper, line{p, q}); }

    // insert a line(segment) whose slope is p, inception is q,
    // and domain is the interval [s, t).
    void insert(const T p, const T q, const T s, const T t) { if(s < t) root = insert(root, lower, upper, line{p, q}, s, t); }

    T get(const T x) const
    {
        assert(!empty());
        line *p = root;
        T l = lower, r = upper;
        T res = p->eval(x);
        while(p)
        {
            T nval = p->eval(x);
            if(comp(nval, res)) res = nval;
            if(r - l <= eps) return res;
            T mid = (l + r) / 2;
            if(x < mid)
            {
                p = p->lch;
                r = mid;
            }
            else
            {
                p = p->rch;
                l = mid;
            }
        }
        return res;
    }
}; // class Li_Chao_tree

#include <cstdio>

main()
{
    int n; long long c;
    scanf("%d%lld",&n,&c);

    Li_Chao_tree cht(0ll,1000001ll);

    for(int i=1; i<n; i++)
    {
        long long h;
        scanf("%lld",&h);
        if(i==1)
        {
            cht.insert(-2*h,h*h+c);
        }
        else
        {
            cht.insert(-2*h,cht.get(h)+h*h*2+c);
        }
    }
    long long hlst;
    scanf("%lld",&hlst);
    printf("%lld\n",cht.get(hlst)+hlst*hlst);
}

Measured memory_bytes: 13492