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() {
  long long int t, n, m, i;
  cin >> t;
  while (t--) {
    long long int term, ans = 0, sum = 0, temp;
    cin >> n >> m;
    term = (n - (n % m)) / m;
    if (m % 10 == 0)
      ans = 0;
    else if (m % 5 == 0) {
      if (term & 1)
        ans = ((term + 1) / 2) * 5;
      else
        ans = (term / 2) * 5;
    } else if (m & 1) {
      ans = (term / 10) * 45;
      temp = term % 10;
      for (i = 0; i < temp; i++) {
        sum = (sum + m) % 10;
        ans += sum;
      }
    } else {
      ans = (term / 5) * 20;
      temp = term % 5;
      for (i = 0; i < temp; i++) {
        sum = (sum + m) % 10;
        ans += sum;
      }
    }
    cout << ans << endl;
  }
}
