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 main() {
  long long t;
  cin >> t;
  vector<long long> v[10];
  v[1] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 0};
  v[2] = {2, 4, 6, 8, 0};
  v[3] = {3, 6, 9, 2, 5, 8, 1, 4, 7, 0};
  v[4] = {4, 8, 2, 6, 0};
  v[5] = {5, 0};
  v[6] = {6, 2, 8, 4, 0};
  v[7] = {7, 4, 1, 8, 5, 2, 9, 6, 3, 0};
  v[8] = {8, 6, 4, 2, 0};
  v[9] = {9, 8, 7, 6, 5, 4, 3, 2, 1, 0};
  v[0] = {0};
  while (t--) {
    long long n, i, j, k, m;
    cin >> n >> m;
    long long x = m % 10;
    long long c = 0;
    long long y = (n / m) / v[x].size();
    long long z = (n / m) % v[x].size();
    for (i = 0; i < v[x].size(); i++) c += v[x][i] * y;
    for (i = 0; i < z; i++) c += v[x][i];
    cout << c << endl;
  }
}
