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 getLastDigit(long long n) {
  if (n < 10) return n;
  return n % 10;
}
void solve() {
  long long n, m;
  cin >> n >> m;
  int ar[10] = {0};
  int index = 0;
  for (long long i = m; i <= n; i += m) {
    ar[index] = getLastDigit(i);
    index++;
    if (index > 9) break;
  }
  if (n >= m) {
    long long result = 0;
    long long div = (n / m);
    div /= 10;
    long long rem = (n / (m * 10));
    rem = (rem * (m * 10));
    rem = (n - rem) / m;
    for (int i = 0; i < 10; i++) {
      result += (ar[i] * div);
    }
    for (int i = 0; i < rem; i++) {
      result += ar[i];
    }
    cout << fixed << setprecision(0) << result << endl;
  } else if (n == m) {
    cout << getLastDigit(m) << endl;
  } else {
    cout << 0 << endl;
  }
}
int main() {
  int T;
  cin >> T;
  while (T--) solve();
}
