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, m, i, r, r1, ans;
    cin >> n >> m;
    if (n < m || m % 10 == 0)
      cout << "0\n";
    else if (n == m)
      cout << n % 10 << "\n";
    else if (m % 2 != 0 && m % 5 != 0) {
      n -= n % m;
      r = n / m;
      if (r >= 10) {
        if (r % 10 != 0) {
          r1 = r - (r % 10);
          r1 = r1 - (r1 / 10);
          ans = (45 * r1) / 9;
          for (i = (m * (r - (r % 10))) + m; i <= n; i += m) {
            ans += i % 10;
          }
          cout << ans << "\n";
        } else {
          r1 = r - (r / 10);
          ans = (45 * r1) / 9;
          cout << ans << "\n";
        }
      } else {
        ans = 0;
        for (i = m; i <= n; i += m) {
          ans += i % 10;
        }
        cout << ans << "\n";
      }
    } else if (m % 5 == 0) {
      n -= n % m;
      r = n / m;
      r1 = r - (r / 2);
      ans = (5 * r1);
      cout << ans << "\n";
    } else {
      n -= n % m;
      r = n / m;
      if (r >= 5) {
        if (r % 5 != 0) {
          r1 = r - (r % 5);
          r1 = r1 - (r1 / 5);
          ans = (20 * r1) / 4;
          for (i = (m * (r - (r % 5))) + m; i <= n; i += m) {
            ans += i % 10;
          }
          cout << ans << "\n";
        } else {
          r1 = r - (r / 5);
          ans = (20 * r1) / 4;
          cout << ans << "\n";
        }
      } else {
        ans = 0;
        for (i = m; i <= n; i += m) {
          ans += i % 10;
        }
        cout << ans << "\n";
      }
    }
  }
}
