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 n, m;
int t, a[100005], f[105];
long long gcd(long long x, long long y) {
  if (x % y == 0) return y;
  return gcd(y, x % y);
}
int main() {
  cin >> t;
  while (t--) {
    cin >> n >> m;
    memset(f, 0, sizeof(f));
    long long k = n / m, t = m % 10, num = 0;
    if (k == 0) {
      cout << 0 << endl;
      continue;
    }
    int s = 0;
    while (1) {
      if (f[t]) break;
      f[t] = 1;
      a[++s] = t;
      num += t;
      t = (t + m) % 10;
    }
    long long tt = k / s, ans = tt * num;
    k -= (tt * s);
    for (int i = 1; i <= k; ++i) ans = ans + a[i];
    cout << ans << endl;
  }
  return 0;
}
