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

public class Main {
    static myScanner sc;
    static PrintWriter pw;

    public static void main(String[] args) throws IOException {
        //setInAndOutPutFromFile("ladder");
        setDefaultInAndOutPut();

        solve();

        pw.flush();
        pw.close();
    }

    static void setDefaultInAndOutPut() {
        sc = new myScanner(new BufferedReader(new InputStreamReader(System.in)));
        pw = new PrintWriter(System.out);
    }

    static void setInAndOutPutFromFile(String s) throws IOException {
        sc = new myScanner(new BufferedReader(new FileReader(new File(s + ".in"))));
        pw = new PrintWriter(new File(s + ".out"));
    }

    static void solve() {
        int t = sc.nextInt();
        for (int i = 0; i < t; i++) {
            long x = sc.nextInt(), y = sc.nextInt(), p = sc.nextInt(), q = sc.nextInt();
            if (p == 0 && x != 0) {
                pw.println(-1);
            } else if (p == q && x < y) {
                pw.println(-1);
            } else {
                long l = 0, r = 1000000001;
                while ((r - l) > 1) {
                    long mid = (l + r) / 2;
                    if (check(mid, q, x, p, y)) {
                        r = mid;
                    } else {
                        l = mid;
                    }
                }
                pw.println(q * r - y);
            }
        }
    }

    static boolean check(long j, long q, long x, long p, long y) {
        return ((q * j) >= y) && ((p * j) >= x) && ((p * j - x) <= (q * j - y));
    }

    static long gcd(long a, long b) {
        if (b == 0)
            return a;
        else
            return gcd(b, a % b);
    }

    static long lcm(long a, long b) {
        return a * b / (gcd(a, b));
    }

}

class myScanner {
    private char[] buffer = new char[1 << 8];
    private int pos = 1;

    private BufferedReader reader;

    public myScanner(BufferedReader reader) {
        this.reader = reader;
    }

    public boolean hasNext() {
        return pos > 0;
    }

    private void loadBuffer() {
        pos = 0;
        try {
            for (int i; (i = reader.read()) != -1; ) {
                char c = (char) i;
                if (c != ' ' && c != '\n' && c != '\t' && c != '\r' && c != '\f') {
                    if (pos == buffer.length) buffer = Arrays.copyOf(buffer, 2 * pos);
                    buffer[pos++] = c;
                } else if (pos != 0) break;
            }
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
    }

    public String current() {
        return String.copyValueOf(buffer, 0, pos);
    }


    public String next() {
        loadBuffer();
        return current();
    }

    public String nextLine() {
        try {
            return reader.readLine();
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
    }


    public int nextInt() {
        return nextInt(10);
    }

    public long nextLong() {
        return nextLong(10);
    }

    public int nextInt(int radix) {
        loadBuffer();
        int result = 0;
        int i = buffer[0] == '-' || buffer[0] == '+' ? 1 : 0;
        for (checkValidNumber(pos > i); i < pos; i++) {
            int digit = buffer[i] - '0';
            checkValidNumber(0 <= digit && digit <= radix - 1);
            result = result * radix + digit;
        }
        return buffer[0] == '-' ? -result : result;
    }

    public long nextLong(int radix) {
        loadBuffer();
        long result = 0;
        int i = buffer[0] == '-' || buffer[0] == '+' ? 1 : 0;
        for (checkValidNumber(pos > i); i < pos; i++) {
            int digit = buffer[i] - '0';
            checkValidNumber(0 <= digit && digit <= radix - 1);
            result = result * radix + digit;
        }
        return buffer[0] == '-' ? -result : result;
    }

    public double nextDouble() {
        loadBuffer();
        long result = 0;
        int i = buffer[0] == '-' || buffer[0] == '+' ? 1 : 0;
        long round = 1;
        final int radix = 10;
        boolean hasPoint = false;
        for (checkValidNumber(pos > i); i < pos; i++) {
            int digit = buffer[i] - '0';
            checkValidNumber((0 <= digit && digit <= radix - 1) || (!hasPoint && digit == -2));
            if (digit == -2) hasPoint = true;
            else {
                if (hasPoint) round *= radix;
                result = result * radix + digit;
            }

        }
        return buffer[0] == '-' ? -result / (1.0 * round) : result / (1.0 * round);
    }

    private void checkValidNumber(boolean condition) {
        if (!condition) throw new NumberFormatException(current());
    }
}