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.
/*
 * Code Author: Akshay Miterani
 * DA-IICT
 */
import java.io.*;
import java.math.*;
import java.util.*;

public class A {

	InputReader in;
	PrintWriter out;
	A() throws IOException {
		in = new InputReader(System.in);
		out = new PrintWriter(System.out);
		//in = new InputReader(new FileInputStream("input_codejam.txt"));
		//out = new PrintWriter(new File("output_codejam.txt"));
		solve();
		out.close();
	}

	public static void main(String args[]) {
		new Thread(null, new Runnable() {
			public void run() {
				try {
					new A();
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		}, "1", 1 << 26).start();
	}

	//--------------------My Code Starts Here----------------------
	long mod=(long)1e9+7;
	public void solve() throws IOException{
		// (x+u)*q = (y+u+v)*p
		// (q-p)u - pv = (py-qx)
		int t=in.nextInt();
		while(t-->0){
			long x=in.nextLong();
			long y=in.nextLong();
			long p=in.nextLong();
			long q=in.nextLong();
			if((p==q && x!=y) || (p==0 && x!=0)){
				out.println("-1");
			}
			else{
				long l=0,h=(long)1e9;
				while(l<=h){
					long m=(l+h)/2;
					if(m*p-x<=m*q-y && m*p-x>=0){
						h=m-1;
					}
					else{
						l=m+1;
					}
				}
				out.println(l*q-y);
			}
		}
	}
	//---------------------My Code Ends Here------------------------
	public static long gcd(long a, long b) {
	    while (b != 0) {
	      long t = b;
	      b = a % b;
	      a = t;
	    }
	    return Math.abs(a);
	  }
	static long modulo(long a,long b,long c) {
		long x=1;
		long y=a;
		while(b > 0){
			if(b%2 == 1){
				x=(x*y)%c;
			}
			y = (y*y)%c; // squaring the base
			b /= 2;
		}
		return  x%c;
	}
	static class Pair implements Comparable<Pair>{
		int x;
		char y;

		Pair(int xx,char yy){
			x=xx;
			y=yy;
		}
		@Override
		public int compareTo(Pair o) {
			if(Long.compare(this.x, o.x)!=0)
				return -Long.compare(this.x, o.x);
			else
				return Long.compare(this.y, o.y);
		}
	}
	public static void debug(Object... o) {
		System.out.println(Arrays.deepToString(o));
	}

	static final class InputReader{
		private final InputStream stream;
		private final byte[] buf=new byte[1024];
		private int curChar;
		private int numChars;
		public InputReader(InputStream stream){this.stream=stream;}
		private int read()throws IOException{
			if(curChar>=numChars){
				curChar=0;
				numChars=stream.read(buf);
				if(numChars<=0)
					return -1;
			}
			return buf[curChar++];
		}
		public final int nextInt()throws IOException{return (int)nextLong();}
		public final long nextLong()throws IOException{
			int c=read();
			while(isSpaceChar(c)){
				c=read();
				if(c==-1) throw new IOException();
			}
			boolean negative=false;
			if(c=='-'){
				negative=true;
				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 negative?(-res):(res);
		}
		public final int[] readIntBrray(int size)throws IOException{
			int[] arr=new int[size];
			for(int i=0;i<size;i++)arr[i]=nextInt();
			return arr;
		}
		public final String next()throws IOException{
			int c=read();
			while(isSpaceChar(c))c=read();
			StringBuilder res=new StringBuilder();
			do{
				res.append((char)c);
				c=read();
			}while(!isSpaceChar(c));
			return res.toString();
		}
		public final String nextLine()throws IOException{
			int c=read();
			while(isSpaceChar(c))c=read();
			StringBuilder res=new StringBuilder();
			do{
				res.append((char)c);
				c=read();
			}while(c!='\n'&&c!=-1);
			return res.toString();
		}
		private boolean isSpaceChar(int c){
			return c==' '||c=='\n'||c=='\r'||c=='\t'||c==-1;
		}
	}
} 