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;
long long int n, m, ar[1000005], sum, t, dp[25], vis[25], pref[25];
void read() { cin >> n >> m; }
long long int add(long long int x, long long int y) { return (x + y) % 10; }
void calcpre(long long int flag) {
  for (int i = 1; i <= flag; i++) pref[i] = pref[i - 1] + dp[i];
}
void calc() {
  long long int cnt = n / m;
  m %= 10;
  long long int flag = 0;
  long long int x = m % 10;
  if (!cnt) return;
  while (!vis[x]) {
    if (cnt <= flag) break;
    x = add(x, 10);
    flag++;
    vis[x]++;
    dp[flag] = x;
    x = add(x, m);
  }
  if (!flag) return;
  calcpre(flag);
  long long int minos = cnt / flag;
  sum += minos * pref[flag];
  minos = cnt % flag;
  sum += pref[minos];
}
void write() { cout << sum << "\n"; }
void reset() {
  sum = 0;
  for (int i = 0; i <= 10; i++) pref[i] = 0, dp[i] = 0, vis[i] = 0;
}
int main() {
  cin.tie(0);
  cout.tie(0);
  ios_base::sync_with_stdio(false);
  cin >> t;
  while (t--) {
    read();
    calc();
    write();
    reset();
  }
}
