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 main() {
  long t = 0;
  cin >> t;
  for (long i = 0; i < t; i++) {
    unsigned long long m, n;
    unsigned long long k = 0;
    cin >> n >> m;
    int s[10];
    unsigned long long sum = s[0] = m % 10;
    int len = 2;
    for (int j = 1; j < 10; j++) {
      s[j] = (s[j - 1] + m) % 10;
      sum += s[j];
      if (s[j] == 0) break;
      len++;
    }
    unsigned long long l = n / m;
    k += l / len * sum;
    for (unsigned long j = 0; j < l % len; j++) k += s[j];
    cout << k << endl;
  }
  return 0;
}
