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 <typename T>
void inpos(T &x) {
  x = 0;
  register T c = getchar();
  while (((c < 48) || (c > 57)) && (c != '-')) c = getchar();
  bool neg = 0;
  if (c == '-') neg = 1;
  for (; c < 48 || c > 57; c = getchar())
    ;
  for (; c > 47 && c < 58; c = getchar()) x = (x << 3) + (x << 1) + (c & 15);
  if (neg) x = -x;
}
template <typename T>
void outpos(T n) {
  if (n < 0) {
    putchar('-');
    n *= -1;
  }
  char snum[65];
  int i = 0;
  do {
    snum[i++] = n % 10 + '0';
    n /= 10;
  } while (n);
  i = i - 1;
  while (i >= 0) putchar(snum[i--]);
}
inline void instr(char *str) {
  register char c = 0;
  register int i = 0;
  while (c < 33) c = getchar();
  while (c != '\n' && c != ' ' && c != EOF) {
    str[i] = c;
    c = getchar();
    ++i;
  }
  str[i] = '\0';
}
long long int getSumFull(long long int d, long long int time = 10) {
  long long int x = d % 10;
  long long int sum = 0;
  for (long long int i = 1; i <= time; i++) {
    sum += (x * i) % 10;
  }
  return sum;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int t;
  cin >> t;
  while (t--) {
    long long int n, d;
    cin >> n >> d;
    long long int elements = n / d;
    cout << getSumFull(d) * (elements / 10) + getSumFull(d, elements % 10)
         << endl;
  }
}
