#include <bits/stdc++.h>
using namespace std;
void solve() {
  long long x, y, p, q;
  cin >> x >> y >> p >> q;
  if (x != y && p == q) {
    cout << "-1\n";
    return;
  }
  if (x != 0 && p == 0) {
    cout << "-1\n";
    return;
  }
  if ((x == 0 && p == 0) || (x == y && p == q)) {
    cout << "0\n";
    return;
  }
  long long ratio = max((x + p - 1) / p, (y + q - 1) / q);
  long long scale_x = ratio * p;
  long long scale_y = ratio * q;
  long long diff = scale_x - x - (scale_y - y);
  if (diff > 0) {
    long long ratio2 = (diff + (q - p) - 1) / (q - p);
    scale_x += ratio2 * p;
    scale_y += ratio2 * q;
  }
  cout << scale_y - y << "\n";
}
int main() {
  int t;
  cin >> t;
  for (int i = 0; i < t; i++) solve();
}

### Prompt

In cpp, your task is to solve the following problem:

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.

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
void solve() {
  long long x, y, p, q;
  cin >> x >> y >> p >> q;
  if (x != y && p == q) {
    cout << "-1\n";
    return;
  }
  if (x != 0 && p == 0) {
    cout << "-1\n";
    return;
  }
  if ((x == 0 && p == 0) || (x == y && p == q)) {
    cout << "0\n";
    return;
  }
  long long ratio = max((x + p - 1) / p, (y + q - 1) / q);
  long long scale_x = ratio * p;
  long long scale_y = ratio * q;
  long long diff = scale_x - x - (scale_y - y);
  if (diff > 0) {
    long long ratio2 = (diff + (q - p) - 1) / (q - p);
    scale_x += ratio2 * p;
    scale_y += ratio2 * q;
  }
  cout << scale_y - y << "\n";
}
int main() {
  int t;
  cin >> t;
  for (int i = 0; i < t; i++) solve();
}

```