#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    long long ns, nl;
    cin >> nl >> ns;
    long long m = ns % 10;
    long long nf = nl / ns;
    long long idn = nf % 10;
    long long f = nf / 10;
    long long arr[10], sum = 0, sum2 = 0;
    for (int i = 0; i < 10; i++) {
      if (i == idn) {
        sum2 = sum;
      }
      arr[i] = (m * (i + 1)) % 10;
      sum += arr[i];
    }
    cout << sum * f + sum2 << endl;
  }
}

### Prompt

Create a solution in Cpp for the following problem:

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 ns, nl;
    cin >> nl >> ns;
    long long m = ns % 10;
    long long nf = nl / ns;
    long long idn = nf % 10;
    long long f = nf / 10;
    long long arr[10], sum = 0, sum2 = 0;
    for (int i = 0; i < 10; i++) {
      if (i == idn) {
        sum2 = sum;
      }
      arr[i] = (m * (i + 1)) % 10;
      sum += arr[i];
    }
    cout << sum * f + sum2 << endl;
  }
}

```