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 = 2e5 + 10;
const int mod = 1e9 + 7;
long long a[100], s[100];
long long n, m, t, mi = 123456789, ans;
int main() {
  cin >> t;
  while (t--) {
    ans = 0;
    scanf("%I64d%I64d", &n, &m);
    long long sum = n / m;
    int i;
    for (i = 1; i <= sum; i++) {
      a[i] = (a[i - 1] + m) % 10;
      s[i] = s[i - 1] + a[i];
      if (i > 1 && a[i] == a[1]) break;
    }
    i--;
    if (i == 0) {
      cout << "0" << endl;
      continue;
    }
    cout << s[i] * (sum / i) + s[sum % i] << endl;
  }
}
