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;
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int t;
  cin >> t;
  while (t--) {
    long long int n, m;
    cin >> n >> m;
    if (n < m) {
      cout << 0 << "\n";
    } else {
      int first[11] = {0};
      long long int sum = 0;
      for (auto i = 1; i < 11; i++) {
        first[i] = (m * i) % 10;
        sum += first[i];
      }
      long long int ans = 0;
      long long int times = n / (m * 10);
      ans = times * sum;
      long long int rem = n - times * (m * 10);
      rem /= m;
      sum = 0;
      for (auto i = 1; i < rem + 1; i++) {
        sum += first[i];
      }
      ans += sum;
      cout << ans << endl;
    }
  }
  return 0;
}
