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>
bool vis[123];
inline void Solve() {
  long long n, m;
  scanf("%lld%lld", &n, &m);
  long long N = n / m;
  for (long long i = 0; i <= 10; ++i) vis[i] = false;
  long long sm = 0, cnt = -1;
  while (true) {
    cnt++;
    long long x = (cnt + 1) * m % 10;
    if (vis[x]) break;
    vis[x] = true;
    sm += x;
  }
  long long ans = (N / cnt) * sm;
  long long st = (N / cnt) * cnt + 1;
  for (long long i = st; i <= N; ++i) ans += 1ll * i * m % 10;
  printf("%lld\n", ans);
}
signed main() {
  long long T;
  scanf("%lld", &T);
  while (T--) Solve();
  return 0;
}
