#include <bits/stdc++.h>
using namespace std;
void make_cycle(long long m, long long& sum_cycle, vector<long long>& arr,
                long long& divider) {
  sum_cycle = 0;
  if (m && 1) {
    arr.resize(11);
    arr[0] = 0;
    divider = m * 10LL;
    for (long long i = 1; i <= 10; i++) {
      arr[i] = (m * i) % 10;
      sum_cycle += arr[i];
    }
  } else {
    arr.resize(6);
    arr[0] = 0;
    divider = m * 5LL;
    for (long long i = 1; i <= 5; i++) {
      arr[i] = (m * i) % 10;
      sum_cycle += arr[i];
    }
  }
}
int main() {
  int t;
  cin >> t;
  while (t--) {
    long long n;
    long long m;
    long long divider;
    cin >> n >> m;
    long long sum_cycle = 0;
    vector<long long> arr;
    make_cycle(m, sum_cycle, arr, divider);
    long long sum_t = (n / divider) * sum_cycle;
    long long remdig = (n % divider) / m;
    for (int i = 1; i <= remdig; i++) {
      sum_t += arr[i];
    }
    cout << sum_t << endl;
  }
  return 0;
}

### Prompt

Please provide a Cpp coded solution to the problem described below:

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

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
void make_cycle(long long m, long long& sum_cycle, vector<long long>& arr,
                long long& divider) {
  sum_cycle = 0;
  if (m && 1) {
    arr.resize(11);
    arr[0] = 0;
    divider = m * 10LL;
    for (long long i = 1; i <= 10; i++) {
      arr[i] = (m * i) % 10;
      sum_cycle += arr[i];
    }
  } else {
    arr.resize(6);
    arr[0] = 0;
    divider = m * 5LL;
    for (long long i = 1; i <= 5; i++) {
      arr[i] = (m * i) % 10;
      sum_cycle += arr[i];
    }
  }
}
int main() {
  int t;
  cin >> t;
  while (t--) {
    long long n;
    long long m;
    long long divider;
    cin >> n >> m;
    long long sum_cycle = 0;
    vector<long long> arr;
    make_cycle(m, sum_cycle, arr, divider);
    long long sum_t = (n / divider) * sum_cycle;
    long long remdig = (n % divider) / m;
    for (int i = 1; i <= remdig; i++) {
      sum_t += arr[i];
    }
    cout << sum_t << endl;
  }
  return 0;
}

```