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;
const long long maxn = 2e5;
long long a[maxn];
long long b[20][30];
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);
  for (long long i = 1; i <= 10; i++) {
    b[1][i] = i;
    b[2][i] = i * 2;
    b[3][i] = i * 3;
    b[4][i] = i * 4;
    b[5][i] = i * 5;
    b[6][i] = i * 6;
    b[7][i] = i * 7;
    b[8][i] = i * 8;
    b[9][i] = i * 9;
  }
  long long t;
  cin >> t;
  while (t--) {
    long long n, m;
    cin >> n >> m;
    long long sum = 0;
    long long cnt = n / m;
    if (m % 10 == 0) {
      cout << 0 << endl;
      continue;
    }
    if (m % 10 == 1) {
      sum += cnt / 10 * 45;
      for (long long i = 0; i <= cnt % 10; i++) {
        sum += b[1][i] % 10;
      }
    }
    if (m % 10 == 2) {
      sum += cnt / 5 * 20;
      for (long long i = 0; i <= cnt % 5; i++) {
        sum += b[2][i] % 10;
      }
    }
    if (m % 10 == 3) {
      sum += cnt / 10 * 45;
      for (long long i = 0; i <= cnt % 10; i++) {
        sum += b[3][i] % 10;
      }
    }
    if (m % 10 == 4) {
      sum += cnt / 5 * 20;
      for (long long i = 0; i <= cnt % 5; i++) {
        sum += b[4][i] % 10;
      }
    }
    if (m % 10 == 5) {
      sum += cnt / 2 * 5;
      for (long long i = 0; i <= cnt % 2; i++) {
        sum += b[5][i] % 10;
      }
    }
    if (m % 10 == 6) {
      sum += cnt / 5 * 20;
      for (long long i = 0; i <= cnt % 5; i++) {
        sum += b[6][i] % 10;
      }
    }
    if (m % 10 == 7) {
      sum += cnt / 10 * 45;
      for (long long i = 0; i <= cnt % 10; i++) {
        sum += b[7][i] % 10;
      }
    }
    if (m % 10 == 8) {
      sum += cnt / 5 * 20;
      for (long long i = 0; i <= cnt % 5; i++) {
        sum += b[8][i] % 10;
      }
    }
    if (m % 10 == 9) {
      sum += cnt / 10 * 45;
      for (long long i = 0; i <= cnt % 10; i++) {
        sum += b[9][i] % 10;
      }
    }
    cout << sum << endl;
  }
  return 0;
}
