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 power_mod(long long int a, long long int x) {
  if (x == 0) return 1;
  long long int y = power_mod(a, x / 2);
  long long int ans = (y * y) % 1000000007;
  if (x % 2) ans = (ans * a) % 1000000007;
  return ans;
}
long long int inv(long long int a) { return power_mod(a, 1000000007 - 2); }
long long int power(long long int a, long long int x) {
  if (x == 0) return 1;
  long long int y = power(a, x / 2);
  long long int ans = (y * y);
  if (x % 2) ans *= a;
  return ans;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int q;
  cin >> q;
  while (q--) {
    long long int n, m;
    set<long long int> st;
    cin >> n >> m;
    long long int c = m % 10;
    long long int s = 0;
    while (st.find(c) == st.end()) {
      s += c;
      st.insert(c);
      c += m;
      c %= 10;
    }
    long long int sz = st.size();
    c = n / m;
    long long int x = c / sz;
    long long int ans = x * s;
    for (long long int i = m * (x * sz + 1); i <= n; i += m) {
      ans += i % 10;
    }
    cout << ans << "\n";
  }
}
