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;
int t;
long long n, m;
int main() {
  scanf("%d", &t);
  while (t--) {
    scanf("%lld%lld", &n, &m);
    long long ans = 0;
    int count = 0;
    for (long long i = m; i <= (n); i += m) {
      ans += i % 10;
      count++;
      if (count == 10) break;
    }
    if (1ll * (n / m) % 10 == 0) {
      long long result = 1ll * ((n / m) / 10) * ans;
      printf("%lld\n", result);
    } else {
      long long result = 1ll * ((n / m) / 10) * ans;
      long long count2 = 1ll * ((n / m)) % 10;
      for (long long i = m; i <= (n); i += m) {
        result += (i % 10);
        count2--;
        if (count2 == 0) break;
      }
      printf("%lld\n", result);
    }
  }
  return 0;
}
