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 round;
  cin >> round;
  unsigned long long int answers[round];
  for (int a = 0; a < round; a++) {
    unsigned long long int n, m, numberOfD, total, sobra, ldm, atual, bla,
        soma = 0;
    vector<int> lNs;
    cin >> n;
    cin >> m;
    if (n < m) {
      answers[a] = 0;
      continue;
    }
    numberOfD = n / m;
    ldm = m % 10;
    atual = ldm;
    while (atual != 0) {
      lNs.push_back(atual);
      atual = atual + ldm;
      atual = atual % 10;
    }
    lNs.push_back(atual);
    for (int i = 0; i < lNs.size(); i++) {
      soma += lNs[i];
    }
    bla = numberOfD / lNs.size();
    total = bla * soma;
    sobra = numberOfD % lNs.size();
    for (int j = 0; j < sobra; j++) {
      total = total + lNs[j];
    }
    answers[a] = total;
  }
  for (int i = 0; i < round; i++) {
    cout << answers[i] << endl;
  }
  return 0;
}
