#include <bits/stdc++.h>
using namespace std;
template <class T>
inline void read(T &x) {
  x = 0;
  register char c = getchar();
  register bool f = 0;
  while (!isdigit(c)) f ^= c == '-', c = getchar();
  while (isdigit(c)) x = x * 10 + c - '0', c = getchar();
  if (f) x = -x;
}
template <class T>
inline void print(T x) {
  if (x < 0) putchar('-'), x = -x;
  if (x > 9) print(x / 10);
  putchar(x % 10 + '0');
}
template <class T>
inline void print(T x, char c) {
  print(x), putchar(c);
}
long long solve(long long n, long long k) {
  function<long long(long long)> locate = [&](long long m) {
    return (m - 1) / (k * k + 1);
  };
  function<pair<long long, long long>(long long)> getkey = [&](long long i) {
    if (!i) return make_pair(k * (k + 1) / 2, k);
    long long j = i / k, t = i % k, oldkey = getkey(j).first;
    long long l = j * (k * k + 1) + t * k + 1,
              r = j * (k * k + 1) + (t + 1) * k, offset = 0;
    if (oldkey <= l)
      offset = k;
    else if (l <= oldkey && oldkey <= r)
      offset = r - oldkey + 1;
    return make_pair((l + r) * k / 2 + offset, r + (offset ? 1 : 0));
  };
  function<long long(long long)> calc = [&](long long n) {
    long long i = locate(n), key = getkey(i).first;
    assert(key != n), n -= key < n;
    long long t = (n - i * (k * k + 1) - 1) / k,
              p = (n - i * (k * k + 1) - 1) % k + 1;
    return (i * k + t) * (k + 1) + p;
  };
  long long i = locate(n), key, from;
  tie(key, from) = getkey(i);
  return key == n ? calc(from) + 1 : calc(n);
}
int main() {
  int T, k;
  long long n;
  for (read(T); T--;) read(n), read(k), print(solve(n, k), '\n');
}
