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>
int main() {
  int t;
  std::cin >> t;
  for (int tt = 0; tt < t; ++tt) {
    unsigned long long n, m, start, sum, cycle = 10e18, res = 0;
    std::cin >> n >> m;
    start = m % 10;
    sum = m % 10;
    for (unsigned long long i = m * 2; i <= n; i += m) {
      if (i % 10 == start) {
        cycle = i - m;
        break;
      }
      sum += i % 10;
    }
    res += sum * (n / cycle);
    n %= cycle;
    for (unsigned long long i = m; i <= n; i += m) res += i % 10;
    std::cout << res << std::endl;
  }
  return 0;
}
