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 sum(int number) {
  int result = 0;
  for (int i = 1; i < 10; i++) {
    result += (i * number) % 10;
  }
  return result;
}
int sum_tail(int number, int count) {
  int result = 0;
  for (int i = 1; i <= count; i++) {
    result += (i * number) % 10;
  }
  return result;
}
int main(int argc, char** argv) {
  int q;
  cin >> q;
  unsigned long long n, m;
  unsigned long long b = 0, count = 0, c = 0;
  unsigned long long a[q];
  int mlast = 0;
  for (int i = 0; i < q; i++) {
    cin >> n >> m;
    mlast = m % 10;
    b = n / m;
    c = 0;
    if (b >= 1) {
      c = b / 10 * sum(mlast);
      int tail = b % 10;
      c += sum_tail(mlast, tail);
    }
    a[i] = c;
  }
  for (int i = 0; i < q; i++) {
    cout << a[i] << endl;
  }
  return 0;
}
