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;
const int N = 5e5 + 5;
const int MOD = 1e9 + 7;
void solve() {
  long long n, m;
  cin >> n >> m;
  long long sz = 0, sum = 0, ls = 0;
  do {
    ls += m;
    ls %= 10;
    sum += ls;
    sz += m;
  } while (ls);
  long long ans = (n / sz) * sum;
  long long id = (n / sz) * sz + m;
  while (id <= n) {
    ls += m;
    ls %= 10;
    ans += ls;
    id += m;
  }
  cout << ans << "\n";
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int q;
  cin >> q;
  for (int i = 0; i < q; ++i) solve();
  return 0;
}
