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.
/*
 * For the brave souls who get this far: You are the chosen ones,
 * the valiant knights of programming who toil away, without rest,
 * fixing our most awful code. To you, true saviors, kings of men,
 * I say this: never gonna give you up, never gonna let you down,
 * never gonna run around and desert you. Never gonna make you cry,
 * never gonna say goodbye. Never gonna tell a lie and hurt you.
 * 
 * And Logic is the strongest weapon. 
 *
 */
//package Coding;

import java.io.*;
import java.math.*;
import java.util.*;
import java.util.Map.Entry;

public class p1 {

    private static InputStream stream;
    private static byte[] buf = new byte[1024];
    private static int curChar;
    private static int numChars;
    private static SpaceCharFilter filter;
    private static PrintWriter pw;
    //pw.print("Case #" + i + ": ");
    //private static int infi = (int) 1e9;
    //private static final int N = 1234567;
    //private static final double MOD = 1e9 + 7;
    //Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));

    public static int soln() {
        int t = nI();
        while (t-- > 0) {
            long ans = 0;
            long x = nL(), y = nL(), p = nL(), q = nL();
            if ((x != y && p == q) || (p == 0 && x != 0)) {
                pw.println("-1");
                continue;
            }
            long le = 1, ri = (long) 1e9;
            while (le <= ri) {
                long m = (le + ri) >> 1;
                long xxx = m * q;
                if ((xxx - y >= m * p - x) && (m * p - x >= 0)) {
                    ans = xxx - y;
                    ri = m - 1;
                } else {
                    le = m + 1;
                }
            }
            pw.println(ans);
        }
        return 0;
    }

    public static void main(String[] args) throws FileNotFoundException {
        InputReader(System.in);
        //pw = new PrintWriter(new FileOutputStream("ans.txt"));
        //pw = new PrintWriter(new FileOutputStream("ans1.txt"));
        pw = new PrintWriter(System.out);
        soln();
        pw.close();
    }

    /*
     *********************************************************************************************
     */
    public static void InputReader(InputStream stream1) {
        stream = stream1;
    }

    private static boolean isWhitespace(int c) {
        return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

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

    private static 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++];
    }

    private static void pIArr(int[] man) {
        int l = man.length;
        for (int i = 0; i < l; i++) {
            pw.print(man[i] + " ");
        }
        pw.println();
    }

    private static void pCArr(char[] man) {
        int l = man.length;
        for (int i = 0; i < l; i++) {
            pw.print(man[i] + " ");
        }
        pw.println();
    }

    private static void pLArr(long[] man) {
        int l = man.length;
        for (int i = 0; i < l; i++) {
            pw.print(man[i] + " ");
        }
        pw.println();
    }

    private static void pDArr(double[] man) {
        int l = man.length;
        for (int i = 0; i < l; i++) {
            pw.print(man[i] + " ");
        }
        pw.println();
    }

    private static void pFArr(float[] man) {
        int l = man.length;
        for (int i = 0; i < l; i++) {
            pw.print(man[i] + " ");
        }
        pw.println();
    }

    private static double nD() {
        return Double.parseDouble(nS());
    }

    private static int nI() {
        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;
    }

    private static long nL() {
        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;
    }

    private static String nS() {
        int c = read();
        while (isSpaceChar(c)) {
            c = read();
        }
        StringBuilder res = new StringBuilder();
        do {
            res.appendCodePoint(c);
            c = read();
        } while (!isSpaceChar(c));
        return res.toString();
    }

    private static String nLi() {
        int c = read();
        while (isSpaceChar(c)) {
            c = read();
        }
        StringBuilder res = new StringBuilder();
        do {
            res.appendCodePoint(c);
            c = read();
        } while (!isEndOfLine(c));
        return res.toString();
    }

    private static boolean isSpaceChar(int c) {
        if (filter != null) {
            return filter.isSpaceChar(c);
        }
        return isWhitespace(c);
    }

    private interface SpaceCharFilter {

        public boolean isSpaceChar(int ch);
    }
}
