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;
int32_t main() {
  long long n;
  cin >> n;
  for (long long i = (0); i < (n); i++) {
    long long m, n;
    cin >> n >> m;
    long long r = m % 10;
    long long num = n / m;
    if (r == 0) {
      cout << 0 << endl;
      continue;
    }
    if (r == 1 || r == 3 || r == 7 || r == 9) {
      long long x = (num / 10) * 45;
      for (long long i = (0); i < (num % 10); i++) {
        x += r * (i + 1) % 10;
      }
      cout << x << endl;
      continue;
    }
    if (r % 2 == 0) {
      long long x = (num / 5) * 20;
      for (long long i = (0); i < (num % 5); i++) {
        x += r * (i + 1) % 10;
      }
      cout << x << endl;
      continue;
    }
    if (r == 5) {
      long long x = (num / 2) * 5;
      for (long long i = (0); i < (num % 2); i++) {
        x += r * (i + 1) % 10;
      }
      cout << x << endl;
      continue;
    }
    return 0;
  }
}
