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() {
  int q;
  cin >> q;
  for (int tt = 0; tt < q; ++tt) {
    long long n, m;
    cin >> n >> m;
    vector<long long> digits;
    long long count = 0;
    long long sumc = 0;
    vector<int> visited(10, 0);
    long long start = 0;
    while (!visited[start]) {
      digits.push_back(start);
      visited[start] = 1;
      sumc += start;
      start = (start + m) % 10;
      ++count;
    }
    long long cycle = count * m;
    long long quotient = n / cycle;
    long long rem = n % cycle;
    long long out = 0;
    for (long long i = 0; i <= rem; i += m) {
      out += (i % 10);
    }
    out += quotient * sumc;
    cout << out << "\n";
  }
  return 0;
}
