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.Scanner;
	import java.io.*;
	import java.util.*;
	import java.math.*;
	import java.lang.*;
	import static java.lang.Math.*;
	 
	public class TestClass implements Runnable
	{
		public static void main(String args[])
		{
			new Thread(null, new TestClass(),"TESTCLASS",1<<26).start();
		}
		public void run()
		{
			//Scanner scan=new Scanner(System.in);
			InputReader hb=new InputReader(System.in);
			PrintWriter w=new PrintWriter(System.out);
			
			int t=hb.nextInt();
			while(t-->0)
			{
				long x=hb.nextLong();
				long y=hb.nextLong();
				long p=hb.nextLong();
				long q=hb.nextLong();
				long start=0;
				long end=2000000000;
				long ans=-1;
				while(start<=end)
				{
					long mid=(start+end)/2;
					long a=mid*p;
					long b=mid*q;
					//w.println(mid+" "+a+" "+b);
					if(a>=x && b>=y && (a-x)<=(b-y))
					{
						ans=b-y;
						end=mid-1;
					}
					else
						start=mid+1;
				}
				w.println(ans);
			}
			w.close();
		}
		
		private void shuffle(char[] arr)
		{
			Random ran = new Random();
			for (int i = 0; i < arr.length; i++) {
				int i1 = ran.nextInt(arr.length);
				int i2 = ran.nextInt(arr.length);

				char temp = arr[i1];
				arr[i1] = arr[i2];
				arr[i2] = temp;
			}
		}
		static class InputReader
		{
			private InputStream stream;
			private byte[] buf = new byte[1024];
			private int curChar;
			private int numChars;
			private SpaceCharFilter filter;
			
			public InputReader(InputStream stream)
			{
				this.stream = stream;
			}
			
			public int read()
			{
				if (numChars==-1) 
					throw new InputMismatchException();
				
				if (curChar >= numChars)
				{
					curChar = 0;
					try 
					{
						numChars = stream.read(buf);
					}
					catch (IOException e)
					{
						throw new InputMismatchException();
					}
					
					if(numChars <= 0)				
						return -1;
				}
				return buf[curChar++];
			}
		 
			public String nextLine()
			{
				BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
				String str = "";
				try
				{
					str = br.readLine();
				}
				catch (IOException e)
				{
					e.printStackTrace();
				}
				return str;
			}
			public int nextInt()
			{
				int c = read();
				
				while(isSpaceChar(c)) 
					c = read();
				
				int sgn = 1;
				
				if (c == '-') 
				{
					sgn = -1;
					c = read();
				}
				
				int res = 0;
				do 
				{
					if(c<'0'||c>'9') 
						throw new InputMismatchException();
					res *= 10;
					res += c - '0';
					c = read();
				}
				while (!isSpaceChar(c)); 
				
				return res * sgn;
			}
			
			public long nextLong() 
			{
				int c = read();
				while (isSpaceChar(c))
					c = read();
				int sgn = 1;
				if (c == '-') 
				{
					sgn = -1;
					c = read();
				}
				long res = 0;
				
				do 
				{
					if (c < '0' || c > '9')
						throw new InputMismatchException();
					res *= 10;
					res += c - '0';
					c = read();
				}
				while (!isSpaceChar(c));
					return res * sgn;
			}
			
			public double nextDouble() 
			{
				int c = read();
				while (isSpaceChar(c))
					c = read();
				int sgn = 1;
				if (c == '-') 
				{
					sgn = -1;
					c = read();
				}
				double res = 0;
				while (!isSpaceChar(c) && c != '.') 
				{
					if (c == 'e' || c == 'E')
						return res * Math.pow(10, nextInt());
					if (c < '0' || c > '9')
						throw new InputMismatchException();
					res *= 10;
					res += c - '0';
					c = read();
				}
				if (c == '.') 
				{
					c = read();
					double m = 1;
					while (!isSpaceChar(c)) 
					{
						if (c == 'e' || c == 'E')
							return res * Math.pow(10, nextInt());
						if (c < '0' || c > '9')
							throw new InputMismatchException();
						m /= 10;
						res += (c - '0') * m;
						c = read();
					}
				}
				return res * sgn;
			}
			
			public String readString() 
			{
				int c = read();
				while (isSpaceChar(c))
					c = read();
				StringBuilder res = new StringBuilder();
				do 
				{
					res.appendCodePoint(c);
					c = read();
				} 
				while (!isSpaceChar(c));
				
				return res.toString();
			}
		 
			public boolean isSpaceChar(int c) 
			{
				if (filter != null)
					return filter.isSpaceChar(c);
				return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
			}
		 
			public String next() 
			{
				return readString();
			}
			
			public interface SpaceCharFilter 
			{
				public boolean isSpaceChar(int ch);
			}
		}
	 
		static class Pair implements Comparable<Pair>
		{
			int a;
			int b;
			String str;
			public Pair(int a,int b)
			{
				this.a=a;
				this.b=b;
				str=min(a,b)+" "+max(a,b);
			}
	 
			public int compareTo(Pair pair)
			{
				if(Integer.compare(a,pair.a)==0)
					return Integer.compare(b,pair.b);
	 
				return Integer.compare(a,pair.a);
			}
		}
	 
		
	}