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;
long long arr[50], arr2[50];
int main() {
  int t;
  cin >> t;
  while (t--) {
    long long n, m;
    cin >> n >> m;
    if (n < m) {
      cout << 0 << endl;
      continue;
    }
    long long p = 0;
    long long tt = 0;
    memset(arr, 0, sizeof(arr));
    long long al = n / m;
    for (int i = 1; i <= al; i++) {
      int oo = m * i % 10;
      if (arr[oo] == 1) {
        break;
      }
      tt += oo;
      arr2[i] = oo;
      arr[oo] = 1;
      p++;
    }
    long long j = al / p * tt;
    long long h = al % p;
    if (h) {
      for (int i = 1; i <= h; i++) {
        j += arr2[i];
      }
    }
    cout << j << endl;
  }
  return 0;
}
