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 getRes(long long a, long long b) {
  long long total = 0;
  for (int i = 1; i < 10; i++) {
    total += (b * i) % 10;
  }
  long long second = b * 10;
  long long first = a / second;
  long long res = total * first;
  if (a % second != 0) {
    for (long long i = b; i <= a % second; i += b) {
      res += (i % 10);
    }
  }
  return res;
}
int main() {
  int q;
  cin >> q;
  long long a, b;
  while (q--) {
    cin >> a >> b;
    if (a < b)
      cout << 0 << endl;
    else
      cout << getRes(a, b) << endl;
  }
  return 0;
}
