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;
long long ab(long long x) { return x > 0LL ? x : -x; }
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long q;
  cin >> q;
  while (q--) {
    long long n, m;
    cin >> n >> m;
    if (m > n) {
      cout << 0 << '\n';
      continue;
    }
    long long f = m % 10;
    long long m1 = m;
    vector<long long> v;
    v.push_back(0);
    while (m1 <= n) {
      v.push_back(m1 % 10);
      m1 += m;
      if (m1 % 10 == f) {
        break;
      }
    }
    for (int i = 1; i < v.size(); i++) v[i] += v[i - 1];
    long long sum = (n / m) / (v.size() - 1) * v[v.size() - 1] +
                    v[(n / m) % (v.size() - 1)];
    cout << sum << '\n';
  }
  return 0;
}
