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;
template <typename T>
void OA(T a[], int l, int r) {
  for (int i = l; i <= r; i++)
    if (i < r)
      cout << a[i] << ' ';
    else
      cout << a[i] << endl;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  int t;
  cin >> t;
  while (t--) {
    long long n, m;
    cin >> n >> m;
    int tmp = 0, num = 0;
    bool vis[20];
    memset(vis, 0, sizeof(vis));
    for (long long i = m; i <= n; i += m) {
      if (vis[i % 10]) break;
      tmp += i % 10;
      vis[i % 10] = 1;
      num++;
    }
    if (num == 0) {
      cout << 0 << endl;
    } else {
      long long p = n / m;
      long long ans = (n / m) / num * tmp;
      p = p % num;
      for (long long i = m; p > 0; i += m, p--) {
        ans += i % 10;
      }
      cout << ans << endl;
    }
  }
}
