#include <bits/stdc++.h>

using namespace std;

#define int long long
// #define double long double
#define FOR(i, a, b) for(ll i = (a); i < (b); ++i)
#define FORR(i, a, b) for(ll i = (a); i > (b); --i)
#define REP(i, n) for(ll i = 0; i < (n); ++i)
#define REPR(i, n) for(ll i = n; i >= 0; i--)
#define FOREACH(x, a) for(auto &(x) : (a))
#define VECCIN(x)                                                              \
    for(auto &youso_ : (x)) cin >> youso_
#define bitcnt __builtin_popcount
#define SZ(x) ((ll)(x).size())
#define fi first
#define se second
#define All(a) (a).begin(), (a).end()
#define rAll(a) (a).rbegin(), (a).rend()
template <typename T = long long> inline T IN() {
    T x;
    cin >> x;
    return (x);
}
inline void CIN() {}
template <class Head, class... Tail>
inline void CIN(Head &&head, Tail &&... tail) {
    cin >> head;
    CIN(move(tail)...);
}
#define CCIN(...)                                                              \
    char __VA_ARGS__;                                                          \
    CIN(__VA_ARGS__)
#define DCIN(...)                                                              \
    double __VA_ARGS__;                                                        \
    CIN(__VA_ARGS__)
#define LCIN(...)                                                              \
    ll __VA_ARGS__;                                                            \
    CIN(__VA_ARGS__)
#define SCIN(...)                                                              \
    string __VA_ARGS__;                                                        \
    CIN(__VA_ARGS__)
#define Printv(v)                                                              \
    {                                                                          \
        REP(x, v.size()) { cout << v[x] << (x == v.size() - 1 ? "\n" : " "); } \
    }
template <typename T = string> inline void eputs(T s) {
    cout << s << "\n";
    exit(0);
}
template <typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val) {
    std::fill((T *)array, (T *)(array + N), val);
}
template <typename T> using PQG = priority_queue<T, vector<T>, greater<T>>;
template <typename T> using PQ = priority_queue<T>;

typedef long long ll;
typedef vector<ll> VL;
typedef vector<VL> VVL;
typedef pair<ll, ll> PL;
typedef vector<PL> VPL;

const int INF = 1e9;
const int MOD = 1e9 + 7;
const double PI = atan(1.0) * 4.0;
const ll LINF = 1e18;
const ll dx[] = {1, 0, -1, 0};
const ll dy[] = {0, 1, 0, -1};

template <int MOD> struct Fp {
    long long val;
    constexpr Fp(long long v = 0) noexcept : val(v % MOD) {
        if(val < 0) v += MOD;
    }
    constexpr int getmod() { return MOD; }
    constexpr Fp operator-() const noexcept { return val ? MOD - val : 0; }
    constexpr Fp operator+(const Fp &r) const noexcept {
        return Fp(*this) += r;
    }
    constexpr Fp operator-(const Fp &r) const noexcept {
        return Fp(*this) -= r;
    }
    constexpr Fp operator*(const Fp &r) const noexcept {
        return Fp(*this) *= r;
    }
    constexpr Fp operator/(const Fp &r) const noexcept {
        return Fp(*this) /= r;
    }
    constexpr Fp &operator+=(const Fp &r) noexcept {
        val += r.val;
        if(val >= MOD) val -= MOD;
        return *this;
    }
    constexpr Fp &operator-=(const Fp &r) noexcept {
        val -= r.val;
        if(val < 0) val += MOD;
        return *this;
    }
    constexpr Fp &operator*=(const Fp &r) noexcept {
        val = val * r.val % MOD;
        return *this;
    }
    constexpr Fp &operator/=(const Fp &r) noexcept {
        long long a = r.val, b = MOD, u = 1, v = 0;
        while(b) {
            long long t = a / b;
            a -= t * b;
            swap(a, b);
            u -= t * v;
            swap(u, v);
        }
        val = val * u % MOD;
        if(val < 0) val += MOD;
        return *this;
    }
    constexpr bool operator==(const Fp &r) const noexcept {
        return this->val == r.val;
    }
    constexpr bool operator!=(const Fp &r) const noexcept {
        return this->val != r.val;
    }
    friend constexpr ostream &operator<<(ostream &os,
                                         const Fp<MOD> &x) noexcept {
        return os << x.val;
    }
    friend constexpr istream &operator>>(istream &is, Fp<MOD> &x) noexcept {
        return is >> x.val;
    }
    friend constexpr Fp<MOD> modpow(const Fp<MOD> &a, long long n) noexcept {
        if(n == 0) return 1;
        auto t = modpow(a, n / 2);
        t = t * t;
        if(n & 1) t = t * a;
        return t;
    }
};

template <typename T, const T id> class convex_hull_trick {
    struct line {
        T a, b;
        line(T a_ = 0, T b_ = 0) : a(a_), b(b_) {}
        T get(T x) { return a * x + b; }
    };
    struct node {
        line l;
        node *lch, *rch;
        node(line l_) : l(l_), lch(nullptr), rch(nullptr) {}
        ~node() {
            if(lch) delete lch;
            if(rch) delete rch;
        }
    };

  private:
    const int n;
    const vector<T> pos;
    node *root;

  public:
    convex_hull_trick(const vector<T> &pos_)
        : n(pos_.size()), pos(pos_), root(nullptr) {}
    ~convex_hull_trick() {
        if(root) delete root;
    }
    void insert(T a, T b) {
        line l(a, b);
        root = modify(root, 0, n - 1, l);
    }
    T get(T x) const {
        int t = lower_bound(pos.begin(), pos.end(), x) - pos.begin();
        assert(t < n && pos[t] == x);
        return sub(root, 0, n - 1, t);
    }

  private:
    node *modify(node *p, int lb, int ub, line &l) {
        if(!p) return new node(l);
        if(p->l.get(pos[lb]) >= l.get(pos[lb]) &&
           p->l.get(pos[ub]) >= l.get(pos[ub]))
            return p;
        if(p->l.get(pos[lb]) <= l.get(pos[lb]) &&
           p->l.get(pos[ub]) <= l.get(pos[ub])) {
            p->l = l;
            return p;
        }
        int c = (lb + ub) / 2;
        if(p->l.get(pos[c]) < l.get(pos[c])) swap(p->l, l);
        if(p->l.get(pos[lb]) <= l.get(pos[lb]))
            p->lch = modify(p->lch, lb, c, l);
        else
            p->rch = modify(p->rch, c + 1, ub, l);
        return p;
    }
    T sub(node *p, int lb, int ub, int t) const {
        if(!p) return id;
        if(ub - lb == 0) return p->l.get(pos[t]);
        int c = (lb + ub) / 2;
        if(t <= c) return max(p->l.get(pos[t]), sub(p->lch, lb, c, t));
        return max(p->l.get(pos[t]), sub(p->rch, c + 1, ub, t));
    }
};

ll dp[200001];

signed main() {
    LCIN(N, C);
    VL H(2000001);
    REP(i, N) { cin >> H[i]; }
    VL tmp = H;
    sort(All(tmp));
    convex_hull_trick<ll, -LINF> cht(tmp);
    tmp.erase(unique(All(tmp)), tmp.end());
    REP(i, N) {
        if(i) {
            dp[i] = -cht.get(H[i]) + H[i] * H[i] + C;
        }
        cht.insert(2 * H[i], -H[i] * H[i] - dp[i]);
    }
    cout << dp[N - 1] << "\n";
}


Measured memory_bytes: 58112