#include <bits/stdc++.h>
using namespace std;
const int MM = 1e5 + 80;
int main() {
  int T;
  long long i, n, m, num, ans, a[20], t, ten;
  cin >> T;
  while (T--) {
    cin >> n >> m;
    num = n / m;
    ten = 0;
    for (i = 1; i <= 9; i++) ten += (m * i) % 10;
    ans = num / 10 * ten;
    num %= 10;
    for (i = 1; i <= num; i++) ans += (i * m) % 10;
    cout << ans << endl;
  }
  return 0;
}

### Prompt

Your task is to create a cpp solution 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;
const int MM = 1e5 + 80;
int main() {
  int T;
  long long i, n, m, num, ans, a[20], t, ten;
  cin >> T;
  while (T--) {
    cin >> n >> m;
    num = n / m;
    ten = 0;
    for (i = 1; i <= 9; i++) ten += (m * i) % 10;
    ans = num / 10 * ten;
    num %= 10;
    for (i = 1; i <= num; i++) ans += (i * m) % 10;
    cout << ans << endl;
  }
  return 0;
}

```