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 long long maxn = 1e16;
const int mod = 1e9 + 7;
void solve() {
  long long n, m;
  cin >> n >> m;
  long long ans = 0, sum = 0;
  vector<int> v;
  int k = m % 10;
  long long p = m;
  while (1) {
    v.push_back(p % 10);
    sum += p % 10;
    p += m;
    if (p % 10 == k) break;
  }
  p -= m;
  ans += (n / p * sum);
  n %= p;
  n /= m;
  for (int i = 0; i < n; i++) ans += v[i];
  cout << ans << '\n';
}
int main() {
  int tt = 1;
  cin >> tt;
  while (tt--) {
    solve();
  }
}
