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::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int q;
  cin >> q;
  while (q--) {
    long long n, m;
    cin >> n >> m;
    if (n < m) {
      cout << 0 << '\n';
      continue;
    }
    int d = m % 10;
    if (d == 5) {
      long long loop = n / m;
      cout << (loop / 2) * 5 + (loop % 2) * 5 << '\n';
      continue;
    } else if (d != 5 && d % 2 != 0) {
      long long loop = n / m;
      int sum[10] = {0};
      sum[0] = d;
      for (auto i = 1; i < 10; i++) sum[i] += sum[i - 1] + ((d * (i + 1)) % 10);
      if (loop % 10 != 0)
        cout << (loop / 10) * 45 + sum[(loop % 10) - 1] << '\n';
      else
        cout << (loop / 10) * 45 << '\n';
      continue;
    } else if (d == 0) {
      cout << 0 << '\n';
      continue;
    } else {
      long long loop = n / m;
      int sum[5] = {0};
      sum[0] = d;
      for (auto i = 1; i < 4; i++) sum[i] += sum[i - 1] + ((d * (i + 1)) % 10);
      if (loop % 5 != 0)
        cout << (loop / 5) * 20 + sum[(loop % 5) - 1] << '\n';
      else
        cout << (loop / 5) * 20 << '\n';
      continue;
    }
  }
  return 0;
}
