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 q;
  cin >> q;
  while (q--) {
    long long n, m, cnt = 0, x, p, i;
    cin >> n >> m;
    p = m;
    if (n < m || m % 10 == 0)
      cout << 0 << endl;
    else {
      if (n == m) {
        cnt += (n % 10);
      } else {
        if (m % 2 == 0) {
          m *= 5;
          x = n / m;
          cnt += (20 * x);
          for (i = m * x; i <= n; i += p) {
            cnt += (i % 10);
          }
        } else if (m % 5 == 0) {
          m *= 2;
          x = n / m;
          cnt += (5 * x);
          for (i = m * x; i <= n; i += p) {
            cnt += (i % 10);
          }
        } else {
          m *= 10;
          x = n / m;
          cnt += (45 * x);
          for (i = m * x; i <= n; i += p) {
            cnt += (i % 10);
          }
        }
      }
      cout << cnt << endl;
    }
  }
  return 0;
}
