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;
void frooty() {
  long long n, m;
  cin >> n >> m;
  if (m % 10 == 5) {
    long long x = n / m;
    if (x % 2 == 1) {
      cout << 5 * (x / 2 + 1) << "\n";
    } else
      cout << 5 * x / 2 << "\n";
  } else if (m % 10 == 0)
    cout << 0 << "\n";
  else if (m % 2 == 0) {
    long long div = n / m;
    long long rem = div / 10;
    long long x = rem * 10;
    long long sum = 40 * rem;
    long long k;
    for (long long i = 1; i <= div - x; i++) {
      k = m * i;
      sum += (k % 10);
    }
    cout << sum << "\n";
  } else {
    long long div = n / m;
    long long rem = div / 10;
    long long x = rem * 10;
    long long sum = 45 * rem;
    long long k;
    for (long long i = 1; i <= div - x; i++) {
      k = m * i;
      sum += (k % 10);
    }
    cout << sum << "\n";
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long t = 1;
  cin >> t;
  while (t--) {
    frooty();
  }
}
