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;
long long int n, m, ar[1000005], sum, t, tut[20], mark[20], pref[20];
void read() { cin >> n >> m; }
void calc() {
  long long int cnt = n / m;
  m %= 10;
  long long int flag = 0;
  long long int x = m % 10;
  if (!cnt) return;
  while (!mark[x] && cnt > flag) {
    x += 10;
    x %= 10;
    flag++;
    mark[x] = 1;
    tut[flag] = x;
    x += m;
    x %= 10;
  }
  if (flag == 0) return;
  for (int i = 1; i <= flag; i++) pref[i] = pref[i - 1] + tut[i];
  long long int minos = cnt / flag;
  sum += minos * pref[flag];
  minos = cnt % flag;
  sum += pref[minos];
}
void write() { cout << sum << "\n"; }
void reset() {
  sum = 0;
  memset(mark, 0, sizeof(mark));
  memset(pref, 0, sizeof(pref));
  memset(tut, 0, sizeof(tut));
}
int main() {
  cin.tie(0);
  cout.tie(0);
  ios_base::sync_with_stdio(false);
  cin >> t;
  while (t--) {
    read();
    calc();
    write();
    reset();
  }
}
