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() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  unsigned short int q;
  cin >> q;
  while (q--) {
    unsigned long long int n, m;
    cin >> n >> m;
    if (n == m)
      cout << m % 10 << "\n";
    else if (n > m) {
      unsigned long long int s = 0;
      if (n > (10 * m)) {
        if (m % 2 == 1) {
          if (m % 5 != 0) {
            s += (n / (10 * m)) * 45;
            for (unsigned long long int i = (n - n % (10 * m) + m); i <= n;
                 i += m) {
              s += i % 10;
            }
            cout << s << "\n";
          } else {
            s += (n / (10 * m)) * 25;
            for (unsigned long long int i = (n - n % (10 * m) + m); i <= n;
                 i += m) {
              s += i % 10;
            }
            cout << s << "\n";
          }
        } else {
          if (m % 10 != 0) {
            s += (n / (10 * m)) * 40;
            for (unsigned long long int i = (n - n % (10 * m) + m); i <= n;
                 i += m) {
              s += i % 10;
            }
            cout << s << "\n";
          } else
            cout << "0\n";
        }
      } else {
        for (unsigned long long int i = m; i <= n; i += m) {
          s += i % 10;
        }
        cout << s << "\n";
      }
    } else
      cout << "0\n";
  }
  return 0;
}
