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.util.*;
import java.io.*;

public class CF412C 
{
	public static void main(String args[]) 
	{
		InputReader in = new InputReader(System.in);
		OutputStream outputStream = System.out;
		PrintWriter out = new PrintWriter(outputStream);
		/*------------------------------My Code starts here------------------------------*/
		int t=in.nextInt();
		long x,y,p,q; 
		while(t-->0)
		{
			x=in.nextLong();
			y=in.nextLong();
			p=in.nextLong();
			q=in.nextLong();
			long l=0,h=(long)1e9;
			while(l<=h)
			{
				long m=(l+h)/2;
				if(p*m>=x && q*m-p*m>=(y-x))
					h=m-1;
				else
					l=m+1;
			}
			if((p==1 && q==1 && x!=y) || (p==0 && x!=0))
				out.println(-1);
			else if(p==0 && x==0)
				out.println(0);
			else
				out.println((long)(l*q-y));
		}
		out.close();
		/*------------------------------The End------------------------------------------*/
	}

	public static final long l = (int) (1e9 + 7);

	private static int[] nextIntArray(InputReader in, int n) {
		int[] a = new int[n];
		for (int i = 0; i < n; i++)
			a[i] = in.nextInt();
		return a;
	}

	private static long[] nextLongArray(InputReader in, int n) {
		long[] a = new long[n];
		for (int i = 0; i < n; i++)
			a[i] = in.nextLong();
		return a;
	}

	private static int[][] nextIntMatrix(InputReader in, int n, int m) {
		int[][] a = new int[n][m];
		for (int i = 0; i < n; i++) {
			for (int j = 0; j < m; j++)
				a[i][j] = in.nextInt();
		}
		return a;
	}

	private static void show(int[] a) {
		for (int i = 0; i < a.length; i++)
			System.out.print(a[i] + " ");
		System.out.println();
	}

	private static void show2DArray(char[][] a) {
		for (int i = 0; i < a.length; i++) {
			for (int j = 0; j < a[0].length; j++)
				System.out.print(a[i][j]);
			System.out.println();
		}
	}

	static class Pair {
		private int first;
		private int second;

		public Pair(int i, int j) {
			this.first = i;
			this.second = j;
		}

		public int getFirst() {
			return first;
		}

		public int getSecond() {
			return second;
		}

		public void setFirst(int k) {
			this.first = k;
		}

		public void setSecond(int k) {
			this.second = k;
		}
	}

	static int modPow(int a, int b, int p) {
		int result = 1;
		a %= p;
		while (b > 0) {
			if ((b & 1) != 0)
				result = (result * a) % p;
			b = b >> 1;
		a = (a * a) % p;
		}
		return result;
	}

	public static void SieveOfEratosthenes(int n) {
		boolean[] prime = new boolean[n + 1];
		Arrays.fill(prime, true);
		prime[1] = false;
		int i, j;
		for (i = 2; i * i <= n; i++) {
			if (prime[i]) {
				for (j = i; j <= n; j += i) {
					if (j != i)
						prime[i] = false;
				}
			}
		}
	}

	static class InputReader {
		public BufferedReader reader;
		public StringTokenizer tokenizer;

		public InputReader(InputStream inputstream) {
			reader = new BufferedReader(new InputStreamReader(inputstream));
			tokenizer = null;
		}

		public String nextLine() {
			String fullLine = null;
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					fullLine = reader.readLine();
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
				return fullLine;
			}
			return fullLine;
		}

		public String next() {
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
			}
			return tokenizer.nextToken();
		}

		public long nextLong() {
			return Long.parseLong(next());
		}

		public int nextInt() {
			return Integer.parseInt(next());
		}
	}

}
