import static java.lang.Math.*;
 
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Arrays;
 
public class Main {
 
	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		MyInput in = new MyInput(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		TaskX solver = new TaskX();
		solver.solve(1, in, out);
		out.close();
	}
 
	static int INF = 1 << 30;
	static long LINF = 1L << 55;
	static int MOD = 1000000007;
	static int[] mh4 = { 0, -1, 1, 0 };
	static int[] mw4 = { -1, 0, 0, 1 };
	static int[] mh8 = { -1, -1, -1, 0, 0, 1, 1, 1 };
	static int[] mw8 = { -1, 0, 1, -1, 1, -1, 0, 1 };
 
	static class TaskX {
 
		public void solve(int testNumber, MyInput in, PrintWriter out) {
 
			int n = in.nextInt();
			long c = in.nextLong();
			long[] h = in.nextLongArray(n);
 
			ConvexHullTrick cht = new ConvexHullTrick(n);
			long[] dp = new long[n];
			Arrays.fill(dp, LINF);
			dp[0] = 0;
			cht.addLine(-2 * h[0], h[0] * h[0] + dp[0]);
 
			for (int i = 1; i < n; i++) {
				dp[i] = min(dp[i], cht.query(h[i]) + h[i] * h[i] + c);
				cht.addLine(-2 * h[i], h[i] * h[i] + dp[i]);
			}
			out.println(dp[n-1]);
		}
 
		/**
		 * 追加クエリの直線の傾きが単調減少の場合
		 * - insert (a, b): add y = ax + b
		 * - query (x)    : min_i{a[i]x + b}
		 * */
		class ConvexHullTrick {
			long[] A, B;
			int len;
 
			public ConvexHullTrick(int n) {
				A = new long[n];
				B = new long[n];
			}
 
			private boolean check(long a, long b) {
				return (B[len - 2] - B[len - 1]) * (a - A[len - 1]) >= (B[len - 1] - b) * (A[len - 1] - A[len - 2]);
			}
 
			public void addLine(long a, long b) {
				while (len >= 2 && check(a, b)) {
					len--;
				}
				A[len] = a;
				B[len] = b;
				len++;
			}
 
			public long query(long x) {
				int l = -1, r = len - 1;
				while (r - l > 1) {
					int mid = (r + l) / 2;
					if (get(mid, x) >= get(mid + 1, x)) {
						l = mid;
					} else {
						r = mid;
					}
				}
				return get(r, x);
			}
 
			private long get(int k, long x) {
				return A[k] * x + B[k];
			}
 
		}
	}
 
	static class MyInput {
		private final BufferedReader in;
		private static int pos;
		private static int readLen;
		private static final char[] buffer = new char[1024 * 8];
		private static char[] str = new char[500 * 8 * 2];
		private static boolean[] isDigit = new boolean[256];
		private static boolean[] isSpace = new boolean[256];
		private static boolean[] isLineSep = new boolean[256];
 
		static {
			for (int i = 0; i < 10; i++) {
				isDigit['0' + i] = true;
			}
			isDigit['-'] = true;
			isSpace[' '] = isSpace['\r'] = isSpace['\n'] = isSpace['\t'] = true;
			isLineSep['\r'] = isLineSep['\n'] = true;
		}
 
		public MyInput(InputStream is) {
			in = new BufferedReader(new InputStreamReader(is));
		}
 
		public int read() {
			if (pos >= readLen) {
				pos = 0;
				try {
					readLen = in.read(buffer);
				} catch (IOException e) {
					throw new RuntimeException();
				}
				if (readLen <= 0) {
					throw new MyInput.EndOfFileRuntimeException();
				}
			}
			return buffer[pos++];
		}
 
		public int nextInt() {
			int len = 0;
			str[len++] = nextChar();
			len = reads(len, isSpace);
			int i = 0;
			int ret = 0;
			if (str[0] == '-') {
				i = 1;
			}
			for (; i < len; i++)
				ret = ret * 10 + str[i] - '0';
			if (str[0] == '-') {
				ret = -ret;
			}
			return ret;
		}
 
		public long nextLong() {
			int len = 0;
			str[len++] = nextChar();
			len = reads(len, isSpace);
			int i = 0;
			long ret = 0;
			if (str[0] == '-') {
				i = 1;
			}
			for (; i < len; i++)
				ret = ret * 10 + str[i] - '0';
			if (str[0] == '-') {
				ret = -ret;
			}
			return ret;
		}
 
		public char nextChar() {
			while (true) {
				final int c = read();
				if (!isSpace[c]) {
					return (char) c;
				}
			}
		}
 
		public String nextString() {
			return new String(nextChars());
		}
 
		public char[] nextChars() {
			int len = 0;
			str[len++] = nextChar();
			len = reads(len, isSpace);
			return Arrays.copyOf(str, len);
		}
 
		public char[][] next2DChars(int h, int w) {
			char[][] s = new char[h][w];
			for (int i = 0; i < h; i++) {
				s[i] = nextChars();
			}
			return s;
		}
 
		int reads(int len, boolean[] accept) {
			try {
				while (true) {
					final int c = read();
					if (accept[c]) {
						break;
					}
					if (str.length == len) {
						char[] rep = new char[str.length * 3 / 2];
						System.arraycopy(str, 0, rep, 0, str.length);
						str = rep;
					}
					str[len++] = (char) c;
				}
			} catch (MyInput.EndOfFileRuntimeException e) {
			}
			return len;
		}
 
		public int[] nextIntArray(final int n) {
			final int[] res = new int[n];
			for (int i = 0; i < n; i++) {
				res[i] = nextInt();
			}
			return res;
		}
 
		public int[] nextIntArray1Index(final int n) {
			final int[] res = new int[n + 1];
			for (int i = 1; i < n + 1; i++) {
				res[i] = nextInt();
			}
			return res;
		}
 
		public int[] nextIntArrayDec(final int n) {
			final int[] res = new int[n];
			for (int i = 0; i < n; i++) {
				res[i] = nextInt() - 1;
			}
			return res;
		}
 
		public long[] nextLongArray(final int n) {
			final long[] res = new long[n];
			for (int i = 0; i < n; i++) {
				res[i] = nextLong();
			}
			return res;
		}
 
		public long[] nextLongArray1Index(final int n) {
			final long[] res = new long[n + 1];
			for (int i = 1; i < n + 1; i++) {
				res[i] = nextLong();
			}
			return res;
		}
 
		public long[] nextLongArrayDec(final int n) {
			final long[] res = new long[n];
			for (int i = 0; i < n; i++) {
				res[i] = nextLong() - 1;
			}
			return res;
		}
 
		public double nextDouble() {
			return Double.parseDouble(nextString());
		}
 
		public double[] nextDoubleArray(int n) {
			double[] res = new double[n];
			for (int i = 0; i < n; i++) {
				res[i] = nextDouble();
			}
			return res;
		}
 
		static class EndOfFileRuntimeException extends RuntimeException {
		}
 
	}
 
}

Measured memory_bytes: 32312