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.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.StringTokenizer;


public class c {
	static int a,b,p,q;
	public static void main(String[] args)throws Exception{
		FastScanner in = new FastScanner(System.in);
		int t = in.nextInt();
		while(t-->0){
			a = in.nextInt();
			b = in.nextInt();
			p = in.nextInt();
			q = in.nextInt();
			int hi = 1000000000, lo = 0;
			while(hi>lo){
				int mid = (hi+lo)/2;
				if(f(mid)!=-1){
					hi = mid;
				} else {
					lo = mid+1;
				}
			}
			System.out.println(f(lo));
		}
	}
	
	static long f(long mult){
		if(mult == 0){
			return -1;
		}
		long ap = p*mult;
		long aq = q*mult;
		long ta = a, tb =b;
		if(ta > ap){
			return -1;
		}
		long correct = ap - ta;
		long ans = correct;
		ta += correct;
		tb += correct;
		if(tb > aq){
			return -1;
		} 
		ans += aq - tb;
		return ans;
	}
	
	
	
	
	
	static class FastScanner {
		BufferedReader br;
		StringTokenizer st;

		public FastScanner(InputStream in) {
			br = new BufferedReader(new InputStreamReader(in));
			st = new StringTokenizer("");
		}

		public String next() throws IOException {
			while (!st.hasMoreElements())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public int nextInt() throws NumberFormatException, IOException {
			return Integer.parseInt(next());
		}
	}
}
