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;
    cin >> n >> m;
    long long ans;
    if (n < m) {
      ans = 0;
    } else if (n == m)
      ans = m % 10;
    else {
      int d = m % 10;
      int rem[10];
      rem[0] = 0;
      for (int i = 1; i < 10; ++i) {
        rem[i] = (i * d) % 10 + rem[i - 1];
      }
      long long tot = n / m;
      ans = rem[tot % 10] + (tot / 10) * rem[9];
    }
    cout << ans << endl;
  }
}
