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
#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    long long int n, k;
    cin >> n >> k;
    long long int m = n;
    if (n < k)
      cout << "0\n";
    else if (n == 1)
      cout << "1\n";
    else if (n <= 10 * k) {
      long long int i = k, ans = 0;
      while (i <= n) {
        ans = ans + i % 10;
        i = i + k;
      }
      cout << ans << "\n";
    } else {
      long long int i = k, ans = 0;
      while (i <= k * 10) {
        ans = ans + i % 10;
        i = i + k;
      }
      long long int p = n / (k * 10);
      ans = ans * p;
      p = p * k * 10 + k;
      while (p <= n) {
        ans = ans + p % 10;
        p = p + k;
      }
      cout << ans << "\n";
    }
  }
  return 0;
}
