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 "03"
using namespace std;
const long long int inf = INT_MAX;
const long long int MOD = 1e9 + 7;
const long long int N = 1e5 + 5;
signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long int q;
  cin >> q;
  while (q--) {
    long long int n, m;
    cin >> n >> m;
    n /= m;
    set<long long int> s;
    m %= 10;
    long long int cur = m;
    map<long long int, long long int> mp;
    long long int c = 1;
    long long int sum = 0;
    while (s.find(cur) == s.end()) {
      cur %= 10;
      s.insert(cur);
      sum += cur;
      mp[c++] = sum;
      cur = (cur + m) % 10;
    }
    long long int ans = n / s.size() * sum + mp[n % s.size()];
    cout << ans << '\n';
  }
  return 0;
}
