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;
void solve() {
  long long n, m, tmp, i;
  cin >> n >> m;
  vector<long long> arr;
  set<long long> s;
  arr.push_back(m % 10);
  s.insert(m % 10);
  for (i = 2 * m;; i += m) {
    tmp = s.size();
    s.insert(i % 10);
    if (s.size() == tmp) break;
    arr.push_back(arr[arr.size() - 1] + (i % 10));
  }
  long long tot = n / m, x = tot / (arr.size());
  long long ans = (x * (arr[arr.size() - 1]));
  long long y = tot % (arr.size());
  if (y != 0) ans += (arr[y - 1]);
  cout << ans << endl;
}
int main() {
  ios_base ::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  int t = 1;
  cin >> t;
  while (t--) solve();
  return 0;
}
