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 mara = (int)(1e6) + 5;
vector<long long> a(mara), prime(mara), v(mara), luck;
map<long long, bool> flag;
long long bigmod(long long a, long long b, long long m) {
  long long res = 1;
  while (b) {
    if (b & 1) {
      res = (res * a) % m;
      b--;
    } else {
      b /= 2;
      a = (a * a) % m;
    }
  }
  return res;
}
void soln() {
  long long a, b, sum = 0;
  cin >> a >> b;
  for (long long i = 1; i <= 10; i++) {
    long long as = i * b;
    as %= 10;
    sum += as;
  }
  long long vajok = 10 * b;
  long long div = a / vajok;
  long long rem = a % vajok;
  long long res = sum * div;
  for (long long i = b; i <= rem; i += b) {
    long long temp = i;
    temp %= 10;
    res += temp;
  }
  cout << res << endl;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  long long t;
  cin >> t;
  while (t--) {
    soln();
  }
  return 0;
}
