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 pii = pair<int, int>;
using pll = pair<long long, long long>;
const long long inf = 0x3f3f3f3f3f3f3f3f;
int cir[20];
void solve() {
  int pos = 0, flag = 0, sum = 0;
  long long n, m, loops;
  cin >> n >> m;
  if (n < m) {
    cout << 0 << '\n';
    return;
  }
  loops = n / m;
  m = m % 10;
  cir[pos++] = m;
  sum += m;
  while (true) {
    cir[pos] = (cir[pos - 1] + m) % 10;
    for (int i = 0; i < pos; i++) {
      if (cir[i] == cir[pos]) flag = 1;
    }
    if (flag) break;
    sum += cir[pos++];
  }
  long long ans = sum * (loops / pos);
  int remain = loops % pos;
  for (int i = 0; i < remain; i++) ans += cir[i];
  cout << ans << '\n';
}
signed main() {
  ios::sync_with_stdio(false), cin.tie(NULL);
  int t;
  cin >> t;
  while (t--) solve();
}
