#include <bits/stdc++.h>
using namespace std;
int main() {
  int testai;
  cin >> testai;
  while (testai--) {
    long long int puslapiai;
    long long int daliklis;
    cin >> puslapiai >> daliklis;
    int suma = 0;
    if (daliklis > puslapiai) {
      cout << 0 << endl;
    } else if (daliklis == puslapiai) {
      cout << daliklis % 10 << endl;
    } else {
      int ikiDesimtSuma = 0;
      for (int i = 1; i <= 10; i++) {
        ikiDesimtSuma += (daliklis * i) % 10;
      }
      long long int telpa = puslapiai / daliklis;
      long long lieka = telpa % 10;
      long long int suma = (telpa - lieka) * ikiDesimtSuma / 10;
      for (int i = 1; i <= lieka; i++) {
        suma += (daliklis * i) % 10;
      }
      cout << suma << endl;
    }
  }
  return 0;
}

### 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 testai;
  cin >> testai;
  while (testai--) {
    long long int puslapiai;
    long long int daliklis;
    cin >> puslapiai >> daliklis;
    int suma = 0;
    if (daliklis > puslapiai) {
      cout << 0 << endl;
    } else if (daliklis == puslapiai) {
      cout << daliklis % 10 << endl;
    } else {
      int ikiDesimtSuma = 0;
      for (int i = 1; i <= 10; i++) {
        ikiDesimtSuma += (daliklis * i) % 10;
      }
      long long int telpa = puslapiai / daliklis;
      long long lieka = telpa % 10;
      long long int suma = (telpa - lieka) * ikiDesimtSuma / 10;
      for (int i = 1; i <= lieka; i++) {
        suma += (daliklis * i) % 10;
      }
      cout << suma << endl;
    }
  }
  return 0;
}

```