#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    long long int n, m;
    cin >> n >> m;
    long long int sum = 0, sum1 = 0, i, j;
    if (m > n) {
      cout << "0" << endl;
    } else {
      i = n / m;
      j = i % 10;
      for (int k = 1; k <= j; k++) {
        sum += (m * k) % 10;
      }
      if (i >= 10) {
        for (int k = 1; k <= 9; k++) sum1 += (m * k) % 10;
        sum1 = sum1 * (i / 10);
      }
      sum = sum + sum1;
      cout << sum << endl;
    }
  }
}

### Prompt

Please provide a cpp coded solution to the problem described below:

Polycarp is reading a book consisting of n pages numbered from 1 to n. Every time he finishes the page with the number divisible by m, he writes down the last digit of this page number. For example, if n=15 and m=5, pages divisible by m are 5, 10, 15. Their last digits are 5, 0, 5 correspondingly, their sum is 10.

Your task is to calculate the sum of all digits Polycarp has written down.

You have to answer q independent queries.

Input

The first line of the input contains one integer q (1 ≤ q ≤ 1000) — the number of queries.

The following q lines contain queries, one per line. Each query is given as two integers n and m (1 ≤ n, m ≤ 10^{16}) — the number of pages in the book and required divisor, respectively.

Output

For each query print the answer for it — the sum of digits written down by Polycarp.

Example

Input


7
1 1
10 1
100 3
1024 14
998244353 1337
123 144
1234312817382646 13


Output


1
45
153
294
3359835
0
427262129093995

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    long long int n, m;
    cin >> n >> m;
    long long int sum = 0, sum1 = 0, i, j;
    if (m > n) {
      cout << "0" << endl;
    } else {
      i = n / m;
      j = i % 10;
      for (int k = 1; k <= j; k++) {
        sum += (m * k) % 10;
      }
      if (i >= 10) {
        for (int k = 1; k <= 9; k++) sum1 += (m * k) % 10;
        sum1 = sum1 * (i / 10);
      }
      sum = sum + sum1;
      cout << sum << endl;
    }
  }
}

```