import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import java.util.BitSet;
import java.util.HashMap;
import java.util.NoSuchElementException;

public class Main {

	public static void main(String[] args) {
		new Main();
	}

	public Main() {
		InputChecker ic = new InputChecker(System.in);
		java.io.PrintWriter out = new java.io.PrintWriter(System.out);
		solve(ic, out);
		out.flush();
	}

	public void solve(InputChecker ic, java.io.PrintWriter out) {
		int T = ic.nextInt(1, 6000);
		if (!isPrime(T)) throw new AssertionError(T + "is not prime");
		ic.readNewLine();
		int sum = 0;
		HashMap<Integer, Data> data = new HashMap<>();
		for (int i : new int[] { 2, 3, 5, 7, 11, 13 }) {
			data.put(i, new Data(i));
		}
		while (T-- > 0) {
			int N = ic.nextInt(1, 300);
			if (!isPrime(N)) throw new AssertionError(N + " is not prime");
			ic.nextChar(' ');
			int P = ic.nextInt(100_000_000, 1_000_000_000);
			if (!isPrime(P)) throw new AssertionError(P + " is not prime");
			ic.readNewLine();
			sum += N;
			int[] A = new int[N];
			for (int i = 0; i < N; ++i) {
				A[i] = ic.nextInt(1, 1_000_000_000);
				if (!isPrime(A[i])) throw new AssertionError(A[i] + " is not prime");
				if (i == N - 1) ic.readNewLine();
				else ic.nextChar(' ');
			}
			for (int i = 2; i < N; ++i) if (A[i] - A[i - 1] != A[1] - A[0])
				throw new AssertionError(Arrays.toString(A) + " is not arithmetic progression"); // 等差数列

			int a = A[0], d = A[1] - A[0];
			long ans = data.get(N).calc(a, d);
			System.out.println(ans % P);
		}
		if (sum > 6000) throw new AssertionError("sum N is over 400: " + sum);
		ic.checkEOF();
	}

	static final class Data {
		int N;

		static final class Search {
			final int N, M, positive;
			final int first;
			final int[] left, right;

			Search(BitSet set, int positive, int N, int M) {
				this.N = N;
				this.M = M;
				this.positive = positive;
				first = set.nextSetBit(0);
				int last = set.previousSetBit(set.length());
				left = new int[last - first + 1];
				right = new int[left.length];
				left[0] = first;
				for (int i = 1; i < left.length; ++i) {
					if (set.get(i + first)) left[i] = i + first;
					else left[i] = left[i - 1];
				}
				right[right.length - 1] = last;
				for (int i = left.length - 1; i >= 0; --i) {
					if (set.get(i + first)) right[i] = i + first;
					else right[i] = right[i + 1];
				}
			}

			long calc(int a, int d) { // 初項a, 公差dの数列
				long weight = (long)a * (2 * positive - M);
				int shift = N * (N + 1) / 2;
				long mid = shift - weight / d;
				if (first >= mid) return Math.abs(weight  + (long) (first - shift) * d); // 最適: a - first d
				int last = first + left.length - 1;
				if (mid >= last) return Math.abs(weight  + (long) (last - shift) * d); // 最適: a - last d
				int l = left[(int) mid - first], r = right[(int) mid - first];
				return Math.min(Math.abs(weight + (long) (l - shift) * d), Math.abs(weight  + (long) (r - shift) * d)); // 最適は隣接するどちらか
			}
		}

		Search[][] compress; // compress[S][x]: {0,1,…,N-1}の部分集合Sに対して、x個を正として選ぶ時に作れる答え

		Data(int N) {
			this.N = N;
			compress = new Search[1 << N][];
			BitSet[][] dp = dp(N);
			for (int i = 1; i < compress.length; ++i) {
				int len = Integer.bitCount(i);
				Search[] array = compress[i] = new Search[len + 1];
				for (int j = 0; j <= len; ++j) array[j] = new Search(dp[i][j], j, N, len);
			}
		}

		private BitSet[][] dp(int N) {
			BitSet[][] dp = new BitSet[1 << N][N + 1]; // dp[S][x]: {0,1,…,N-1}の部分集合Sに対して、x個を正として選ぶ時に作れる総和
			int mid = N * (N + 1) / 2, setLen = mid << 1 | 1;
			for (int i = 0; i < dp.length; ++i) {
				int len = Integer.bitCount(i);
				{ // 初項
					dp[i][len] = new BitSet(setLen); // 全部を正で選ぶ
					int sum = mid;
					for (int j = 0; j < N; ++j) if ((i >> j & 1) != 0) sum += j;
					dp[i][len].set(sum);
				}
				for (int j = 0; j < len; ++j) {
					dp[i][j] = new BitSet(setLen);
					for (int k = 0; k < N; ++k) {
						if ((i >> k & 1) == 0) continue;
						dp[i][j].or(dp[i ^ 1 << k][j].get(k, setLen));
					}
				}
			}
			return dp;
		}

		long calc(int a, int d) {
			long sum = 0;
			for (int i = 1; i < compress.length; ++i) {
				long min = Long.MAX_VALUE;
				for (Search s : compress[i]) {
					long calc = s.calc(a, d);
					min = Math.min(min, calc);
				}
				sum += min;
			}
			return sum;
		}
	}

	public static class Barrett {
		private final int mod;
		private final long h, l;
		private final long MAX = 1L << 62;
		private final int MASK = (1 << 31) - 1;

		Barrett(final int mod) {
			this.mod = mod;
			final long t = MAX / mod;
			h = t >>> 31;
			l = t & MASK;
		}

		int reduce(final long x) {
			final long xh = x >>> 31, xl = x & MASK;
			long z = xl * l;
			z = xl * h + xh * l + (z >>> 31);
			z = xh * h + (z >>> 31);
			int ret = (int) (x - z * mod);
			return ret < 0 || ret >= mod ? ret - mod : ret;
		}
	}

	private static boolean isSPRP(Barrett n, int a) {
		int d = n.mod - 1, s = Integer.numberOfTrailingZeros(d);
		d >>= s;
		int cur = 1, pw = d;
		do {
			if ((pw & 1) != 0) cur = n.reduce((long) cur * a);
			a = n.reduce((long) a * a);
			pw >>= 1;
		} while (pw != 0);
		if (cur == 1) return true;
		while (s-- > 0) {
			if (cur == n.mod - 1) return true;
			cur = n.reduce((long) cur * cur);
		}
		return false;
	}

	private static final int bases[] = { 15591, 2018, 166, 7429, 8064, 16045, 10503, 4399, 1949, 1295, 2776, 3620, 560,
			3128, 5212, 2657, 2300, 2021, 4652, 1471, 9336, 4018, 2398, 20462, 10277, 8028, 2213, 6219, 620, 3763, 4852,
			5012, 3185, 1333, 6227, 5298, 1074, 2391, 5113, 7061, 803, 1269, 3875, 422, 751, 580, 4729, 10239, 746,
			2951, 556, 2206, 3778, 481, 1522, 3476, 481, 2487, 3266, 5633, 488, 3373, 6441, 3344, 17, 15105, 1490, 4154,
			2036, 1882, 1813, 467, 3307, 14042, 6371, 658, 1005, 903, 737, 1887, 7447, 1888, 2848, 1784, 7559, 3400,
			951, 13969, 4304, 177, 41, 19875, 3110, 13221, 8726, 571, 7043, 6943, 1199, 352, 6435, 165, 1169, 3315, 978,
			233, 3003, 2562, 2994, 10587, 10030, 2377, 1902, 5354, 4447, 1555, 263, 27027, 2283, 305, 669, 1912, 601,
			6186, 429, 1930, 14873, 1784, 1661, 524, 3577, 236, 2360, 6146, 2850, 55637, 1753, 4178, 8466, 222, 2579,
			2743, 2031, 2226, 2276, 374, 2132, 813, 23788, 1610, 4422, 5159, 1725, 3597, 3366, 14336, 579, 165, 1375,
			10018, 12616, 9816, 1371, 536, 1867, 10864, 857, 2206, 5788, 434, 8085, 17618, 727, 3639, 1595, 4944, 2129,
			2029, 8195, 8344, 6232, 9183, 8126, 1870, 3296, 7455, 8947, 25017, 541, 19115, 368, 566, 5674, 411, 522,
			1027, 8215, 2050, 6544, 10049, 614, 774, 2333, 3007, 35201, 4706, 1152, 1785, 1028, 1540, 3743, 493, 4474,
			2521, 26845, 8354, 864, 18915, 5465, 2447, 42, 4511, 1660, 166, 1249, 6259, 2553, 304, 272, 7286, 73, 6554,
			899, 2816, 5197, 13330, 7054, 2818, 3199, 811, 922, 350, 7514, 4452, 3449, 2663, 4708, 418, 1621, 1171,
			3471, 88, 11345, 412, 1559, 194 };

	public static boolean isPrime(final int x) {
		if (x == 2 || x == 3 || x == 5 || x == 7) return true;
		if ((x & 1) == 0 || x % 3 == 0 || x % 5 == 0 || x % 7 == 0) return false;
		if (x < 121) return x > 1;
		return checkPrime(x);
	}

	private static boolean checkPrime(final int x) {
		if (x < 121) return x > 1;
		long h = x;
		h = (h >> 16 ^ h) * 0x45d9f3b;
		h = (h >> 16 ^ h) * 0x45d9f3b;
		h = (h >> 16 ^ h) & 0xFF;
		return isSPRP(new Barrett(x), bases[(int) h]);
	}

	public static int exponent10(int n, int e) {
		return n * pow(10, e);
	}

	public static long exponent10L(int n, int e) {
		return n * pow(10L, e);
	}

	public static int pow(int a, int b) {
		int ans = 1;
		for (int mul = a; b > 0; b >>= 1, mul *= mul) if ((b & 1) != 0) ans *= mul;
		return ans;
	}

	public static long pow(long a, long b) {
		long ans = 1;
		for (long mul = a; b > 0; b >>= 1, mul *= mul) if ((b & 1) != 0) ans *= mul;
		return ans;
	}

	public static class CharSet {
		private final BitSet set = new BitSet(256);

		public void add(char... c) {
			for (char i : c) set.set(i);
		}

		public void add(CharSet... s) {
			for (CharSet i : s) set.or(i.set);
		}

		public boolean contains(char... c) {
			for (char i : c) if (!set.get(i)) return false;
			return true;
		}

		public boolean contains(String s) {
			return contains(s.toCharArray());
		}

		private static final class Chars extends CharSet {
			public Chars(char... c) {
				super.add(c);
			}

			public Chars(CharSet... s) {
				super.add(s);
			}

			@Override
			public void add(char... c) {
				throw new UnsupportedOperationException();
			}

			@Override
			public void add(CharSet... s) {
				throw new UnsupportedOperationException();
			}
		}

		public static final CharSet NUMBER = new Chars('0', '1', '2', '3', '4', '5', '6', '7', '8', '9');
		public static final CharSet LOWER = new Chars('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
				'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z');
		public static final CharSet UPPER = new Chars('A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
				'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z');
		public static final CharSet ALPHABET = new Chars(LOWER, UPPER);

	}

	public static class InputChecker {
		private InputStream in;
		private final byte[] buffer = new byte[1024];
		private final byte[] undo = new byte[1024];
		private int undoSize = 0;
		private int read = 0;
		private int length = 0;

		public InputChecker(InputStream in) {
			this.in = in;
		}

		public final void setInputStream(InputStream in) { this.in = in; }

		public final void setInputStream(File in) {
			try {
				this.in = new FileInputStream(in);
			} catch (FileNotFoundException e) {
				e.printStackTrace();
			}
		}

		private boolean hasNextByte() {
			if (undoSize > 0) return true;
			if (read < length) return true;
			read = 0;
			try {
				length = in.read(buffer);
			} catch (IOException e) {
				e.printStackTrace();
			}
			return length > 0;
		}

		private byte readByte() {
			if (hasNextByte()) return undoSize > 0 ? undo[--undoSize] : buffer[read++];
			throw new NoSuchElementException();
		}

		private void undo(byte b) {
			undo[undoSize++] = b;
		}

		private void undo(char c) {
			if ((c & 0xFF80) == 0) {
				undo((byte) c);
				return;
			}
			undo((byte) (c & 0x3F | 0x80));
			if ((c & 0xF800) == 0) {
				undo((byte) (c >> 6 & 0x1F | 0xC0));
			} else {
				undo((byte) (c >> 6 & 0x3F | 0x80));
				undo((byte) (c >> 12 | 0xE0));
			}
		}

		public final boolean hasNext() {
			return hasNextByte();
		}

		public final char nextChar() {
			byte b = readByte();
			if ((b & 0x80) == 0) return (char) b;
			if ((b & 0x20) == 0) return (char) ((b & 0x1F) << 6 | readByte() & 0x3F);
			return (char) ((b & 0xF) << 12 | (readByte() & 0x3F) << 6 | readByte() & 0x3F);
		}

		public final char nextChar(char estimate) {
			char c = nextChar();
			if (estimate == c) return estimate;
			undo(c);
			throw new AssertionError();
		}

		public final char nextChar(CharSet estimate) {
			char c = nextChar();
			if (estimate.contains(c)) return c;
			undo(c);
			throw new AssertionError();
		}

		public final void readNewLine() {
			char c = nextChar();
			if (c == '\r') {
				c = nextChar();
				if (c != '\n') undo(c);
				return;
			} else if (c == '\n') return;
			undo(c);
			throw new AssertionError();
		}

		public final void checkEOF() {
			if (hasNextByte()) throw new AssertionError();
		}

		public final String next(CharSet contains) {
			StringBuilder sb = new StringBuilder();
			try {
				do {
					char c = nextChar();
					if (!contains.contains(c)) {
						undo(c);
						return sb.toString();
					}
					sb.append(c);
				} while (true);
			} catch (NoSuchElementException e) {
				if (sb.length() <= 0) throw new AssertionError();
				return sb.toString();
			}
		}

		public final int nextInt() {
			byte b = readByte();
			int n = 0;
			if (b == '-') {
				if (!isNumber(b = readByte())) {
					undo(b);
					throw new NumberFormatException();
				}
				try {
					if (b == '0') {
						if (!isNumber(b = readByte())) {
							undo(b);
							return 0;
						}
						throw new NumberFormatException();
					}
					do n = Math.addExact(Math.multiplyExact(n, 10), '0' - b); while (isNumber(b = readByte()));
					undo(b);
				} catch (NoSuchElementException e) {}
				return n;
			}
			if (!isNumber(b)) {
				undo(b);
				throw new NumberFormatException();
			}
			try {
				if (b == '0') {
					if (!isNumber(b = readByte())) {
						undo(b);
						return 0;
					}
					throw new NumberFormatException();
				}
				do n = Math.addExact(Math.multiplyExact(n, 10), b - '0'); while (isNumber(b = readByte()));
				undo(b);
			} catch (NoSuchElementException e) {}
			return n;
		}

		public final int nextInt(int min, int max) {
			int n = nextInt();
			if (min <= n && n <= max) return n;
			throw new NumberFormatException();
		}

		private static boolean isNumber(byte c) {
			return '0' <= c && c <= '9';
		}

		public final long nextLong() {
			byte b = readByte();
			long n = 0;
			if (b == '-') {
				if (!isNumber(b = readByte())) {
					undo(b);
					throw new NumberFormatException();
				}
				try {
					if (b == '0') {
						if (!isNumber(b = readByte())) {
							undo(b);
							return 0;
						}
						throw new NumberFormatException();
					}
					do n = Math.addExact(Math.multiplyExact(n, 10), '0' - b); while (isNumber(b = readByte()));
					undo(b);
				} catch (NoSuchElementException e) {}
				return n;
			}
			if (!isNumber(b)) {
				undo(b);
				throw new NumberFormatException();
			}
			try {
				if (b == '0') {
					if (!isNumber(b = readByte())) {
						undo(b);
						return 0;
					}
					throw new NumberFormatException();
				}
				do n = Math.addExact(Math.multiplyExact(n, 10), b - '0'); while (isNumber(b = readByte()));
				undo(b);
			} catch (NoSuchElementException e) {}
			return n;
		}

		public final long nextLong(long min, long max) {
			long n = nextLong();
			if (min <= n && n <= max) return n;
			throw new NumberFormatException();
		}

		public final double nextDouble() {
			StringBuilder sb = new StringBuilder();
			byte b = readByte();
			if (b == '-') {
				sb.append(b);
				b = readByte();
			}
			if (b == '0') {
				sb.append(b);
				b = readByte();
			} else {
				while (isNumber(b)) {
					sb.append(b);
					b = readByte();
				}
			}
			if (b == '.') {
				sb.append(b);
				b = readByte();
				while (isNumber(b)) {
					sb.append(b);
					b = readByte();
				}
			}
			if (b == 'e' || b == 'E') {
				sb.append(b);
				b = readByte();
				if (b == '-' || b == '+') {
					sb.append(b);
					b = readByte();
				}
				while (isNumber(b)) {
					sb.append(b);
					b = readByte();
				}
			}
			undo(b);
			return Double.parseDouble(sb.toString());
		}
	}
}