#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    long long int n, k, ans, temp, rem, sum = 0, temp_temp;
    cin >> n >> k;
    temp_temp = k;
    if (k > n)
      ans = 0;
    else {
      int num[10];
      for (int i = 0; i < 10; i++) {
        num[i] = temp_temp % 10;
        temp_temp = temp_temp + k;
        sum += num[i];
      }
      temp = n / k;
      rem = temp % 10;
      temp = temp / 10;
      ans = sum * temp;
      for (int i = 0; i < rem; i++) ans += num[i];
    }
    cout << ans << endl;
  }
}

### Prompt

Develop a solution in cpp 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, k, ans, temp, rem, sum = 0, temp_temp;
    cin >> n >> k;
    temp_temp = k;
    if (k > n)
      ans = 0;
    else {
      int num[10];
      for (int i = 0; i < 10; i++) {
        num[i] = temp_temp % 10;
        temp_temp = temp_temp + k;
        sum += num[i];
      }
      temp = n / k;
      rem = temp % 10;
      temp = temp / 10;
      ans = sum * temp;
      for (int i = 0; i < rem; i++) ans += num[i];
    }
    cout << ans << endl;
  }
}

```