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.*;
import java.lang.Math.*;

public class MainA {

	public static int mod = 20000;
	public static long[] val;
	public static long[] arr;
	static int max = (int) 1e9 + 7;

	public static void main(String[] args) {

		InputReader in = new InputReader(System.in);
		PrintWriter out = new PrintWriter(System.out);
		int t=in.nextInt();
		while(t-->0)
		{
			int x=in.nextInt();
			int y=in.nextInt();
			int p=in.nextInt();
			int q=in.nextInt();
			if(p==0 && x!=0){out.println(-1);continue;}if(p==0 && x==0){out.println(0);continue;}
			if(p==q && x!=y){out.println(-1);continue;}if(p==q && x==y){out.println(0);continue;}
			
			double a=(double)x/p;
			double b=(double)y/q;
			if((long)x*(long)q==(long)y*(long)p)
			{
				out.println(0);continue;
				
			}
			else if((long)x*(long)q<(long)y*(long)p)
			{
				long c=(long)Math.ceil(b);int flag=0;
				
				long l=c;long r=(int)1e9+1;
				long ret=c*q-y;
				while(l<=r)
				{
					long mid=(l+r)/2;
					if(mid*q-y == mid*p-x)
					{
						out.println(mid*q-y);flag=1;break;
					}
					if(mid*q - y >mid*p -x )
					{
						ret=mid*q-y;
						r=mid-1;
					}
					else 
					{
						l=mid+1;
					}
	
				}
				if(flag==1)continue;
				out.println(ret);
			}
			else
			{
				int flag=0;
				long c=(long)Math.ceil(a);
				long l=c;long r=(int)1e9+1;
				long ret=c*q-y;
				while(l<=r)
				{
					long mid=(l+r)/2;
					if(mid*q-y == mid*p-x)
					{
						out.println(mid*q-y);flag=1;break;
					}
					if(mid*q - y >mid*p -x )
					{
						ret=mid*q-y;
						r=mid-1;
					}
					else 
					{
						l=mid+1;
					}
	
				}
				if(flag==1)continue;
				out.println(ret);
			}
			
		}
		out.close();
	}

	static void swap(Pairs arr[], int i, int j) {
		Pairs t = arr[i];
		arr[i] = arr[j];
		arr[j] = t;
	}

	static int partition(Pairs arr[], int l, int h) {
		long x = arr[h].x;
		int i = (l - 1);

		for (int j = l; j <= h - 1; j++) {
			if (arr[j].x <= x) {
				i++;
				// swap arr[i] and arr[j]
				swap(arr, i, j);
			}
		}
		// swap arr[i+1] and arr[h]
		swap(arr, i + 1, h);
		return (i + 1);
	}

	// Sorts arr[l..h] using iterative QuickSort
	static void sort(Pairs arr[], int l, int h) {
		// create auxiliary stack
		int stack[] = new int[h - l + 1];

		// initialize top of stack
		int top = -1;

		// push initial values in the stack
		stack[++top] = l;
		stack[++top] = h;

		// keep popping elements until stack is not empty
		while (top >= 0) {
			// pop h and l
			h = stack[top--];
			l = stack[top--];

			// set pivot element at it's proper position
			int p = partition(arr, l, h);

			// If there are elements on left side of pivot,
			// then push left side to stack
			if (p - 1 > l) {
				stack[++top] = l;
				stack[++top] = p - 1;
			}

			// If there are elements on right side of pivot,
			// then push right side to stack
			if (p + 1 < h) {
				stack[++top] = p + 1;
				stack[++top] = h;
			}
		}
	}

	static class Pairs implements Comparable<Pairs> {
		long x;
		int y;

		Pairs(long a, int b) {
			x = a;
			y = b;
		}

		@Override
		public int compareTo(Pairs o) {
			// TODO Auto-generated method stub
			if (x == o.x)
				return Integer.compare(y, o.y);
			else
				return Long.compare(x, o.x);
		}

	}

	public static void debug(Object... o) {
		System.out.println(Arrays.deepToString(o));
	}

	public static boolean isPal(String s) {
		for (int i = 0, j = s.length() - 1; i <= j; i++, j--) {
			if (s.charAt(i) != s.charAt(j))
				return false;
		}
		return true;
	}

	public static String rev(String s) {
		StringBuilder sb = new StringBuilder(s);
		sb.reverse();
		return sb.toString();
	}

	public static long gcd(long x, long y) {
		if (y == 0)
			return x;
		if (x % y == 0)
			return y;
		else
			return gcd(y, x % y);
	}

	public static int gcd(int x, int y) {
		if (x % y == 0)
			return y;
		else
			return gcd(y, x % y);
	}

	public static long gcdExtended(long a, long b, long[] x) {

		if (a == 0) {
			x[0] = 0;
			x[1] = 1;
			return b;
		}
		long[] y = new long[2];
		long gcd = gcdExtended(b % a, a, y);

		x[0] = y[1] - (b / a) * y[0];
		x[1] = y[0];

		return gcd;
	}

	public static int abs(int a, int b) {
		return (int) Math.abs(a - b);
	}

	public static long abs(long a, long b) {
		return (long) Math.abs(a - b);
	}

	public static int max(int a, int b) {
		if (a > b)
			return a;
		else
			return b;
	}

	public static int min(int a, int b) {
		if (a > b)
			return b;
		else
			return a;
	}

	public static long max(long a, long b) {
		if (a > b)
			return a;
		else
			return b;
	}

	public static long min(long a, long b) {
		if (a > b)
			return b;
		else
			return a;
	}

	public static long[][] mul(long a[][], long b[][]) {
		long c[][] = new long[2][2];
		c[0][0] = a[0][0] * b[0][0] + a[0][1] * b[1][0];
		c[0][1] = a[0][0] * b[0][1] + a[0][1] * b[1][1];
		c[1][0] = a[1][0] * b[0][0] + a[1][1] * b[1][0];
		c[1][1] = a[1][0] * b[0][1] + a[1][1] * b[1][1];

		return c;
	}

	public static long[][] pow(long n[][], long p, long m) {
		long result[][] = new long[2][2];
		result[0][0] = 1;
		result[0][1] = 0;
		result[1][0] = 0;
		result[1][1] = 1;

		if (p == 0)
			return result;
		if (p == 1)
			return n;
		while (p != 0) {
			if (p % 2 == 1)
				result = mul(result, n);
			//System.out.println(result[0][0]);
			for (int i = 0; i < 2; i++) {
				for (int j = 0; j < 2; j++) {
					if (result[i][j] >= m)
						result[i][j] %= m;
				}
			}

			p >>= 1;
			n = mul(n, n);
			// System.out.println(1+" "+n[0][0]+" "+n[0][1]+" "+n[1][0]+" "+n[1][1]);
			for (int i = 0; i < 2; i++) {
				for (int j = 0; j < 2; j++) {
					if (n[i][j] >= m)
						n[i][j] %= m;
				}
			}
		}
		return result;
	}

	public static long pow(long n, long p) {
		long result = 1;
		if (p == 0)
			return 1;
		if (p == 1)
			return n;
		while (p != 0) {
			if (p % 2 == 1)
				result *= n;
			p >>= 1;
			n *= n;
		}
		return result;
	}

	static class InputReader {

		private final InputStream stream;
		private final byte[] buf = new byte[8192];
		private int curChar, snumChars;
		private SpaceCharFilter filter;

		public InputReader(InputStream stream) {
			this.stream = stream;
		}

		public int snext() {
			if (snumChars == -1)
				throw new InputMismatchException();
			if (curChar >= snumChars) {
				curChar = 0;
				try {
					snumChars = stream.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (snumChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}

		public int nextInt() {
			int c = snext();
			while (isSpaceChar(c)) {
				c = snext();
			}
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = snext();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = snext();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public long nextLong() {
			int c = snext();
			while (isSpaceChar(c)) {
				c = snext();
			}
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = snext();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = snext();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public int[] nextIntArray(int n) {
			int a[] = new int[n];
			for (int i = 0; i < n; i++) {
				a[i] = nextInt();
			}
			return a;
		}

		public long[] nextLongArray(int n) {
			long a[] = new long[n];
			for (int i = 0; i < n; i++) {
				a[i] = nextInt();
			}
			return a;
		}

		public String readString() {
			int c = snext();
			while (isSpaceChar(c)) {
				c = snext();
			}
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = snext();
			} while (!isSpaceChar(c));
			return res.toString();
		}

		public String nextLine() {
			int c = snext();
			while (isSpaceChar(c))
				c = snext();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = snext();
			} while (!isEndOfLine(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;
		}

		private boolean isEndOfLine(int c) {
			return c == '\n' || c == '\r' || c == -1;
		}

		public interface SpaceCharFilter {
			public boolean isSpaceChar(int ch);
		}
	}
}