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;
string to_string(string s) { return "\"" + s + "\""; }
template <typename T>
string to_string(vector<T>);
template <typename U, typename V>
string to_string(pair<U, V> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
template <typename T>
string to_string(vector<T> v) {
  string r = "[";
  for (int i = 0; i < (int)v.size() - 1; i++) r += to_string(v[i]) + ", ";
  if (!v.empty()) r += to_string(v.back());
  return r + "]";
}
void solve() {
  long long int n, m, cnt, k, d;
  vector<long long int> a, f;
  scanf("%lld%lld", &n, &m);
  cnt = n / m;
  ;
  m %= 10;
  ;
  d = m;
  a.push_back(d);
  d = (d + m) % 10;
  while (d != a.front()) {
    a.push_back(d);
    d = (d + m) % 10;
  }
  k = (long long int)a.size();
  ;
  f.assign(k, cnt / k);
  cnt %= k;
  for (int i = 0; i < cnt; i++) f[i]++;
  long long int ans = 0;
  for (int i = 0; i < k; i++) ans += f[i] * a[i];
  printf("%lld\n", ans);
}
int main() {
  long long int q;
  scanf("%lld", &q);
  while (q--) solve();
}
