#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<queue>
#include<map>
#include<math.h>
#include<iomanip>
#include<set>
#include<numeric>
#include<cstring>
#include<cstdio>
#include<functional>
#include<bitset>
#include<limits.h>
#include<cassert>
#include<iterator>
#include<complex>
#include<stack>
#include<unordered_map>
#include<unordered_set>
#include<time.h>
#include<random>
#include<array>
using namespace std;
using ll = long long;
#define rep(i, a, b) for(int i = a; i < b; i++)
#define rrep(i, a, b) for(int i = b - 1; i >= a; i--)
#define ALL(a) a.begin(), a.end()
using pii = pair<int,int>;
using piii = pair<pii,int>;
using pll = pair<long long, long long>;
using plll = pair<pll, long long>;
// #pragma GCC optimize("Ofast")
#define pcnt __builtin_popcount
#define buli(x) __builtin_popcountll(x)
#define pb push_back
#define mp make_pair
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );
#define isSquare(x) (sqrt(x)*sqrt(x) == x)
template<class T>bool chmax(T &a, const T &b) {if(a<b){a = b; return 1;} return 0; };
template<class T>bool chmin(T &a, const T &b) {if(a>b){a = b; return 1;} return 0; };
inline void in(void){return;}
template <typename First, typename... Rest> void in(First& first, Rest&... rest){cin >> first;in(rest...);return;}
inline void out(void){cout << "\n";return;}
template <typename First, typename... Rest> void out(First first, Rest... rest){cout << first << " ";out(rest...);return;}
const double EPS = 1e-9;
const int mod = 1e9 + 7;
const int INF = 1e9;
const long long INFLL = 1e18;
void iosetup() {
    cin.tie(nullptr);ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
}
template< typename T1, typename T2 >
ostream &operator<<(ostream &os, const pair< T1, T2 >& p) {
    os << p.first << " " << p.second;
    return os;
}
template< typename T1, typename T2 >
istream &operator>>(istream &is, pair< T1, T2 > &p) {
    is >> p.first >> p.second;
    return is;
}
template< typename T >
ostream &operator<<(ostream &os, const vector< T > &v) {
    for(int i = 0; i < (int) v.size(); i++) {
        os << v[i] << (i + 1 != v.size() ? " " : "");
    }
    return os;
}
template< typename T >
istream &operator>>(istream &is, vector< T > &v) {
    for(T &in : v) is >> in;
    return is;
}
template <typename T> void Exit(T first){cout << first << endl;exit(0); };
template< int mod > struct ModInt {
    int x; ModInt() : x(0) {}
    ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}
    ModInt &operator+=(const ModInt &p) {if((x += p.x) >= mod) x -= mod;return *this;}
    ModInt &operator-=(const ModInt &p) {if((x += mod - p.x) >= mod) x -= mod;return *this;}
    ModInt &operator*=(const ModInt &p) {x = (int) (1LL * x * p.x % mod);return *this;}
    ModInt &operator/=(const ModInt &p) {*this *= p.inverse();return *this;}
    ModInt operator-() const { return ModInt(-x); }
    ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }
    ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }
    ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }
    ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }
    bool operator==(const ModInt &p) const { return x == p.x; }
    bool operator!=(const ModInt &p) const { return x != p.x; }
    ModInt inverse() const {int a = x, b = mod, u = 1, v = 0, t;
    while(b > 0) { t = a / b; swap(a -= t * b, b); swap(u -= t * v, v); }return ModInt(u);}
    ModInt pow(int64_t n) const {ModInt ret(1), mul(x); while(n > 0) {if(n & 1) ret *= mul;mul *= mul;n >>= 1;}return ret;}
    friend ostream &operator<<(ostream &os, const ModInt &p) { return os << p.x;}
    friend istream &operator>>(istream &is, ModInt &a) { int64_t t; is >> t; a = ModInt< mod >(t); return (is); }
    static int get_mod() { return mod; }
}; using modint = ModInt< mod >;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};

// https://kazuma8128.hatenablog.com/entry/2018/02/28/102130
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));
    }
};

int main(){
    iosetup();
    ll N, C; cin >> N >> C;
    vector<ll> h(N); cin >> h;
    vector<ll> dp(N, INFLL);
    dp[0] = 0;
    convex_hull_trick<ll, -INFLL> cht(h);
    cht.insert(2 * h[0], -h[0] * h[0]);
    rep(i, 1, N){
        dp[i] = -cht.get(h[i]) + C + h[i] * h[i];
        cht.insert(2 * h[i], -h[i] * h[i] - dp[i]);
    }
    // cerr << dp << endl;
    cout << dp[N-1] << endl;

    return 0;
}

Measured memory_bytes: 14336