#include <bits/stdc++.h>

using namespace std;

using LL = long long;
using PII = pair<int, int>;
using ll = long long;
using DBL = double;
using VI = vector<int>;
using VD = vector<DBL>;
using VVI = vector<VI>;
using VVD = vector<VD>;

#define FOR(i,a,b) for(int i = a; i < b; i++)
#define REP(i,n) FOR(i,0,n)
#define SZ(a) ((int)((a).size()))
#define ALL(x) (x).begin(), (x).end()
#define SET(a,v) memset((a), (v), sizeof(a))
#define EB emplace_back
#define PB push_back
#define MP make_pair
#define ST first
#define ND second

//#define trace(...) {__f(#__VA_ARGS__, __VA_ARGS__);}
//template<typename Arg> void __f(const char* name, Arg&& arg) {
//  cerr << name << " = " << arg << std::endl;
//} template <typename Arg1, typename... Args>
//void __f(const char* names, Arg1&& arg1, Args&&... args) {
//  const char* comma = strchr(names + 1, ',');
//  cerr.write(names, comma - names) << " = " << arg1<<" | ";__f(comma+1, args...); }
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
//using namespace __gnu_pbds; // OST: find_by_order, order_of_key
//typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
//#pragma GCC optimize("Ofast")
//optimize("unroll-loops")
//target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
///*** RNGS ***/
//SEED=chrono::steady_clock::now().time_since_epoch().count();
//// or high_resolution_clock
//mt19937 rng(SEED); /*or*/ random_device rd; mt19937 rng(rd());
//uniform_int_distribution<> dis(MIN, MAX);// usage: dis(rng)
//struct chash {int operator()(int x) const {return x^SEED;}};
//gp_hash_table<int,int,chash>m;//use cc if very less updates
///*** FAST IO ***/
//inline int scan(){ bool y=0; int x=0; char c=getchar_unlocked();
//while(c<'0'||c>'9'){ if(c=='-')y=1; c=getchar_unlocked();}
//while(c>='0'&&c<='9'){x=(x<<1)+(x<<3)+c-'0';c=getchar_unlocked();}
//return y?-x:x; }

const int MAXN = 200010;
int h[MAXN];
long long dp[MAXN];

class line {
public:
    long long m, c;
    line(long long _m, long long _c) {
        m = _m;
        c = _c;
    }
};

bool operator<(const line&a, const line &b) {
    return a.m < b.m;
}

double getIntersection(const line&a, const line &b) {
    return (a.c - b.c)/((double) b.m - a.m);
}

int main() {
    #ifdef LOCAL_EXEC
//    freopen("sample.in", "r", stdin);
//    freopen("sample.out", "w", stdout);
    #else
    ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
    #endif
    int n;
    long long c;
    cin >> n >> c;
    for(int i=1; i<=n; ++i) {
        cin >> h[i];
    }
    dp[n] = 0;
    deque<pair<double, line>> cht;
    cht.PB({1e25, line(-2ll*h[n], h[n]*1ll*h[n] + dp[n])});
    for(int i=n-1; i>=1; --i) {
        auto it = lower_bound(cht.begin(), cht.end(), MP((double)h[i], line(-1e18, -1e18)));
        dp[i] = it->second.m * 1ll * h[i] + it->second.c + h[i] * 1ll * h[i] + c;
        auto newLine = line(-2ll*h[i], h[i]*1ll*h[i] + dp[i]);
        while(cht.front().first <= getIntersection(cht.front().second, newLine)) {
            cht.pop_front();
        }
        cht.push_front({getIntersection(cht.front().second, newLine), newLine});
    }
    cout << dp[1] << endl;
	return 0;
}


Measured memory_bytes: 10664