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>
#pragma GCC optimize(3)
using namespace std;
int main(int argc, char** argv) {
  int q;
  cin >> q;
  while (q--) {
    long long n, m;
    cin >> n >> m;
    long long x = m % 10;
    long long y = 0, s = 0;
    vector<int> v;
    bool f[11] = {0};
    while (f[x] == 0) {
      v.push_back(x);
      s += x;
      y += m;
      f[x] = 1;
      x += m;
      x %= 10;
    }
    long long d = n / y;
    long long ans = d * s;
    long long r = n % y;
    for (long long i = m, j = 0; i <= r; i += m, j++) {
      j %= (v.size());
      ans += v[j];
    }
    cout << ans << endl;
  }
  return 0;
}
