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 int gcd(long long int n, long long int m) {
  if (m == 0) return n;
  if (n < m) swap(n, m);
  while (n % m != 0) {
    long long int temp = n;
    n = m;
    m = temp % m;
  }
  return m;
}
bool comp(pair<long long int, long long int> &p1,
          pair<long long int, long long int> &p2) {
  return p1.second < p2.second;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long int t;
  cin >> t;
  while (t--) {
    long long int n, m, x, y, i, sum = 0, ans = 0;
    cin >> n >> m;
    y = n / m;
    m = m % 10;
    if (m == 0) {
      cout << 0 << '\n';
      continue;
    }
    if (gcd(m, 10ll) == 1)
      x = 10;
    else if (gcd(m, 10ll) == 2)
      x = 5;
    else
      x = 2;
    i = m;
    while (i != 0) {
      sum += i;
      i = i + m;
      i = i % 10;
    }
    long long int z = y / x;
    ans = sum * z;
    y = y % x;
    i = m;
    while (y != 0) {
      ans += i;
      i = i + m;
      i = i % 10;
      y--;
    }
    cout << ans << '\n';
  }
  return 0;
}
