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;
long long tab[12], pr[12];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int q;
  cin >> q;
  long long n, m, w, x;
  for (int z = 0; z < q; z++) {
    cin >> n >> m;
    x = 1;
    for (long long i = 1; i <= 11; i++) {
      tab[i] = (tab[i - 1] + (m % 10)) % 10;
      pr[i] = pr[i - 1] + tab[i];
      if (tab[i] == tab[1] && i > 1) {
        x = i - 1;
        break;
      }
    }
    w = pr[x] * (n / (x * m));
    n %= x * m;
    w += pr[n / m];
    cout << w << "\n";
  }
  return 0;
}
