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 + 7;
const int mod = 1e9 + 7;
const int B = sqrt(N);
int n, k;
int a[N];
int b[N];
vector<int> v;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  int T;
  cin >> T;
  while (T--) {
    long long x, y;
    cin >> x >> y;
    long long ans = 0;
    if (y == 1) {
      long long g = x / 10;
      ans = g * 9 * 10 / 2;
      ans += (x % 10) * (x % 10 + 1) / 2;
    } else {
      long long g = x / y;
      long long f = y;
      long long cnt = 0;
      for (int i = 1; i <= 10; i++) {
        cnt += f % 10;
        f += y;
      }
      f = y;
      ans += g / 10 * cnt;
      for (int i = 1; i <= g % 10; i++) {
        ans += f % 10;
        f += y;
      }
    }
    cout << ans << "\n";
  }
}
