#include <iostream>
#include <vector>
#include <cstdio>
#define task "CWALKWAY"
using namespace std;
using ll = long long;
using ld = long double;

template<class T>
void read(T &x){
    register int c;
    x = 0;
    while((c = getchar()) && c < '0' || c > '9');
    for(; c >= '0' && c <= '9'; c = getchar())
        x = x * 10 + c - '0';
}

const int N = 1e6 + 2;
int n;
ll c, a[N];

void Read(){
    read(n); read(c);
    for(int i = 1; i <= n; ++i)
        read(a[i]);
}

vector<int> line;
vector<ld> point;
ll dp[N];
const ll Inf = 1e15 + 7;
int last = 0;

ll bp(ll v){
    return v * v;
}

ld f(int i, int j){
    return (ld) 1.0 * (dp[i - 1] + bp(a[i]) - dp[j - 1] - bp(a[j])) / (-2ll * a[j] + 2ll * a[i]);
}

void Solve(){
    line.push_back(1);
    point.push_back(-Inf);
    dp[1] = c;
    dp[0] = 0;
    for(int i = 2; i <= n; ++i){
        while(last < point.size() && point[last] < a[i])
            ++last;
        --last;
        dp[i] = c + dp[i - 1];
        dp[i] = min(dp[i], c + bp(a[i]) + bp(a[line[last]]) + dp[line[last] - 1] - 2ll * (a[line[last]]) * a[i]);
        while(line.size() > 1){
            if( (a[i] == a[line.back()] && dp[i - 1] < dp[line.back() - 1]) ||
                (a[i] != a[line.back()] && f(i, line[line.size() - 1]) <= f(i, line[line.size() - 2])))
            {
                line.pop_back();
                point.pop_back();
                continue;
            }
            break;
        }
        last = min(last, (int)point.size() - 1);
        if(a[i] != a[line.back()] || dp[i - 1] < dp[line.back() - 1]){
            point.push_back(f(i, line.back()));
            line.push_back(i);
        }
    }
    cout << dp[n];
}

main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0); if(fopen(task".INP", "r"))
    freopen(task".INP", "r", stdin),
    freopen(task".OUT", "w", stdout);
    Read();
    Solve();
}