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;
string s;
int arr[1000001];
int main() {
  int q;
  cin >> q;
  while (q--) {
    long long ans = 0;
    long long n, m;
    long long c = 0;
    cin >> n >> m;
    if (m > n) {
      cout << 0 << endl;
      continue;
    }
    long long i = 2;
    long long sum = (m) % 10;
    bool f = false;
    while (true) {
      if ((m * i) % 10 == m % 10) break;
      if (m * i > n) {
        f = true;
        cout << sum << endl;
        break;
      }
      sum += ((m * i) % 10);
      i++;
    }
    i--;
    if (f) continue;
    long long d = m * i;
    ans = (n / d) * sum;
    for (long long i1 = (n / d) * d + m; i1 <= n; i1 += m) ans += (i1 % 10);
    cout << ans << endl;
  }
  return 0;
}
