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;
using ll = long long;
ll solve(ll N, ll M) {
  auto k = N / M;
  if (k == 0) return 0;
  ll p = 0, len = 0;
  set<ll> rs;
  for (ll i = 1; i <= k; ++i) {
    auto r = (i * M) % 10;
    if (rs.count(r) == 1) break;
    rs.insert(r);
    ++p;
    len += r;
  }
  auto ans = (k / p) * len;
  auto left = (k % p);
  for (ll i = 1; i <= left; ++i) {
    auto r = (i * M) % 10;
    ans += r;
  }
  return ans;
}
int main() {
  ios::sync_with_stdio(false);
  int Q;
  cin >> Q;
  while (Q--) {
    ll N, M;
    cin >> N >> M;
    auto ans = solve(N, M);
    cout << ans << '\n';
  }
  return 0;
}
