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() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int q;
  cin >> q;
  while (q--) {
    long long n, m;
    cin >> n >> m;
    vector<long long> a;
    if (n >= m)
      a.push_back(m % 10);
    else {
      cout << "0\n";
      continue;
    }
    for (long long i = 2 * m; i <= n; i += m) {
      if (i % 10 != a[0])
        a.push_back(i % 10);
      else
        break;
    }
    long long x = (n / m) / (long long)(a.size());
    long long y = (n / m) % (long long)(a.size());
    long long u = 0, v = 0;
    for (int i = 0; i < a.size(); i++) {
      if (i < y) u += a[i];
      v += a[i];
    }
    cout << v * x + u << "\n";
  }
}
