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;
using namespace std;
pair<vector<long long>, long long> getDigits(long long number) {
  vector<long long> v;
  long long sum = 0, i = number, mod = i % 10;
  v.reserve(10);
  do {
    v.push_back(mod);
    sum += (mod);
    i += number;
    mod = i % 10;
  } while (mod != v.front());
  return make_pair(v, sum);
}
int main() {
  int q;
  cin >> q;
  long long m, n, acc;
  vector<long long> results;
  results.reserve(q);
  while (q--) {
    cin >> n >> m;
    long long div = n / m;
    auto digits = getDigits(m);
    auto v = digits.first;
    auto s = digits.second;
    acc = (div / v.size()) * s;
    auto top = div % v.size();
    acc = accumulate(v.begin(), v.begin() + top, acc);
    results.push_back(acc);
  }
  for (auto r : results) {
    cout << r << "\n";
  }
  return 0;
}
