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;
template <class T>
inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
const double EPS = 1e-7;
const int INF = 1 << 30;
const long long int LLINF = 1LL << 60;
const double PI = acos(-1);
const int MOD = 1000000007;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};
void solve() {
  long long int n, m;
  cin >> n >> m;
  string tmp = to_string(m);
  long long int r = tmp.back() - '0';
  vector<long long int> v;
  long long int now = r;
  while (1) {
    bool ok = true;
    for (long long int i : v) {
      if (i == now) {
        ok = false;
      }
    }
    if (!ok) {
      break;
    }
    v.emplace_back(now);
    (now += r) %= 10LL;
  }
  long long int sum = accumulate((v).begin(), (v).end(), 0LL);
  long long int sz = v.size();
  long long int cnt = n / m;
  long long int ans = (cnt / sz) * sum;
  for (long long int i = 0; i < (cnt % sz); i++) {
    ans += v[i];
  }
  cout << ans << "\n";
}
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int t;
  cin >> t;
  while (t--) {
    solve();
  }
}
