#include <bits/stdc++.h>
using namespace std;
const int INF = 0x3f3f3f3f;
const long long LINF = 0x3f3f3f3f3f3f3f3f;
const int MOD = 1e9 + 7;
template <typename S, typename T>
inline bool Min(S &a, const T &b) {
  return a > b ? a = b, true : false;
}
template <typename S, typename T>
inline bool Max(S &a, const T &b) {
  return a < b ? a = b, true : false;
}
template <typename S, typename T>
inline void Adm(S &a, const T &b) {
  a = (a + b) % MOD;
  if (a < 0) a += MOD;
}
template <typename S, typename T>
inline void Mum(S &a, const T &b) {
  a = 1LL * a * b % MOD;
}
template <typename T>
inline bool IsPri(T x) {
  if (x < 2) return false;
  for (T i = 2; i * i <= x; ++i)
    if (x % i == 0) return false;
  return true;
}
template <typename T>
inline T Gcd(T a, T b) {
  while (b) {
    T t = b;
    b = a % b;
    a = t;
  }
  return a;
}
template <typename T>
inline int BitCnt(T x) {
  int cnt = 0;
  while (x) ++cnt, x &= x - 1;
  return cnt;
}
template <typename T>
inline T MDis(T x1, T y1, T x2, T y2) {
  return abs(x1 - x2) + abs(y1 - y2);
}
template <typename T>
inline T MDis(T x1, T y1, T z1, T x2, T y2, T z2) {
  return abs(x1 - x2) + abs(y1 - y2) + abs(z1 - z2);
}
inline double EDis(double x1, double y1, double x2, double y2) {
  return sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));
}
inline double EDis(double x1, double y1, double z1, double x2, double y2,
                   double z2) {
  return sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2) +
              (z1 - z2) * (z1 - z2));
}
inline long long Pow(long long a, long long n) {
  long long t = 1;
  a %= MOD;
  while (n > 0) {
    if (n & 1) t = t * a % MOD;
    a = a * a % MOD, n >>= 1;
  }
  return t % MOD;
}
inline int read() {
  static char buf[1000000], *p1 = buf, *p2 = buf;
  register int x = false;
  register char ch =
      p1 == p2 && (p2 = (p1 = buf) + fread(buf, 1, 1000000, stdin), p1 == p2)
          ? EOF
          : *p1++;
  ;
  register bool sgn = false;
  while (ch != '-' && (ch < '0' || ch > '9'))
    ch = p1 == p2 && (p2 = (p1 = buf) + fread(buf, 1, 1000000, stdin), p1 == p2)
             ? EOF
             : *p1++;
  ;
  if (ch == '-')
    sgn = true,
    ch = p1 == p2 && (p2 = (p1 = buf) + fread(buf, 1, 1000000, stdin), p1 == p2)
             ? EOF
             : *p1++;
  ;
  while (ch >= '0' && ch <= '9')
    x = (x << 1) + (x << 3) + (ch ^ 48),
    ch = p1 == p2 && (p2 = (p1 = buf) + fread(buf, 1, 1000000, stdin), p1 == p2)
             ? EOF
             : *p1++;
  ;
  return sgn ? -x : x;
}
long long calc(long long n, long long m) {
  long long q = n / (m + 1);
  long long d = (n - q + m - 1) / m;
  long long s = (d - (n - q) % d) % d;
  long long e = (q + 1) + (m - 1) * d;
  long long res = ((q + 1) + e) * m / 2;
  res = res * d - e * s;
  return res;
}
int main() {
  int T;
  cin >> T;
  while (T--) {
    long long n, m, p = 0;
    cin >> n >> m;
    if (m * 2 > n) p = m - n / 2, m = n / 2;
    cout << (m ? calc(n, m) : 0) + p << endl;
  }
  return 0;
}
