You are an experienced Codeforces user. Today you found out that during your activity on Codeforces you have made y submissions, out of which x have been successful. Thus, your current success rate on Codeforces is equal to x / y.

Your favorite rational number in the [0;1] range is p / q. Now you wonder: what is the smallest number of submissions you have to make if you want your success rate to be p / q?

Input

The first line contains a single integer t (1 ≤ t ≤ 1000) — the number of test cases.

Each of the next t lines contains four integers x, y, p and q (0 ≤ x ≤ y ≤ 109; 0 ≤ p ≤ q ≤ 109; y > 0; q > 0).

It is guaranteed that p / q is an irreducible fraction.

Hacks. For hacks, an additional constraint of t ≤ 5 must be met.

Output

For each test case, output a single integer equal to the smallest number of submissions you have to make if you want your success rate to be equal to your favorite rational number, or -1 if this is impossible to achieve.

Example

Input

4
3 10 1 2
7 14 3 8
20 70 2 7
5 6 1 1


Output

4
10
0
-1

Note

In the first example, you have to make 4 successful submissions. Your success rate will be equal to 7 / 14, or 1 / 2.

In the second example, you have to make 2 successful and 8 unsuccessful submissions. Your success rate will be equal to 9 / 24, or 3 / 8.

In the third example, there is no need to make any new submissions. Your success rate is already equal to 20 / 70, or 2 / 7.

In the fourth example, the only unsuccessful submission breaks your hopes of having the success rate equal to 1.
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.io.PrintStream;
import java.util.HashMap;
import java.util.Map;
import java.util.StringTokenizer;

/*
 public class _807C {

 }

 */

public class _807C
{
	public void solve() throws FileNotFoundException
	{
		InputStream inputStream = System.in;

		InputHelper inputHelper = new InputHelper(inputStream);

		PrintStream out = System.out;

		// actual solution
		int t = inputHelper.readInteger();

		while (t-- > 0)

		{
			long x = inputHelper.readInteger();
			long y = inputHelper.readInteger();

			long p = inputHelper.readInteger();
			long q = inputHelper.readInteger();

			// if (x == 0 && p == 0)
			// {
			// System.out.println("0");
			// continue;
			// }
			// else if (x == 0 || p == 0)
			// {
			// System.out.println("-1");
			// continue;
			// }
			//
			// long gcd = gcd(x, y);
			// long rx = x / gcd;
			// long ry = y / gcd;
			//
			// if (rx == p && ry == q)
			// {
			// System.out.println("0");
			// continue;
			// }

			long lo = 1;
			long hi = (long) 2e9;

			long ans = Long.MAX_VALUE;
			while (lo <= hi)
			{
				long mid = (lo + hi) / 2;
				long cp = p * mid;
				long cq = q * mid;

				if (cp >= x && cq >= y && cp - x <= cq - y)
				{
					ans = Math.min(cq - y, ans);
					hi = mid - 1;
				}
				else if (cp >= x && cq >= y && cp - x > cq - y)
				{
					lo = mid + 1;
				}
				else if (cp < x || cq < y)
				{
					lo = mid + 1;
				}
			}

			if (ans == Long.MAX_VALUE)
			{
				System.out.println("-1");
			}
			else
			{
				System.out.println(ans);
			}
		}
		// end here
	}

	long gcd(long a, long b)
	{
		if (b == 0)
			return a;
		else
			return gcd(b, a % b);
	}

	public static void main(String[] args) throws FileNotFoundException
	{
		(new _807C()).solve();
	}

	class InputHelper
	{
		StringTokenizer tokenizer = null;
		private BufferedReader bufferedReader;

		public InputHelper(InputStream inputStream)
		{
			InputStreamReader inputStreamReader = new InputStreamReader(
					inputStream);
			bufferedReader = new BufferedReader(inputStreamReader, 16384);
		}

		public String read()
		{
			while (tokenizer == null || !tokenizer.hasMoreTokens())
			{
				try
				{
					String line = bufferedReader.readLine();
					if (line == null)
					{
						return null;
					}
					tokenizer = new StringTokenizer(line);
				}
				catch (IOException e)
				{
					e.printStackTrace();
				}
			}

			return tokenizer.nextToken();
		}

		public Integer readInteger()
		{
			return Integer.parseInt(read());
		}

		public Long readLong()
		{
			return Long.parseLong(read());
		}
	}
}