#include <bits/stdc++.h>
using namespace std;
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  long long int t, n, m, a, nl, ml;
  cin >> t;
  long long int arr[10];
  while (t--) {
    cin >> n >> m;
    nl = n % 10;
    ml = m % 10;
    for (long long int i = 0; i < 10; i++) arr[i] = ((i + 1) * ml) % 10;
    long long int sum = 0;
    sum = accumulate(arr, arr + 10, 0LL);
    n = n / m;
    sum = n / 10 * sum;
    for (long long int i = 0; i < n % 10; i++) sum += arr[i];
    cout << sum << endl;
  }
}

### Prompt

Please create a solution in Cpp to 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;
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  long long int t, n, m, a, nl, ml;
  cin >> t;
  long long int arr[10];
  while (t--) {
    cin >> n >> m;
    nl = n % 10;
    ml = m % 10;
    for (long long int i = 0; i < 10; i++) arr[i] = ((i + 1) * ml) % 10;
    long long int sum = 0;
    sum = accumulate(arr, arr + 10, 0LL);
    n = n / m;
    sum = n / 10 * sum;
    for (long long int i = 0; i < n % 10; i++) sum += arr[i];
    cout << sum << endl;
  }
}

```