//Nguyen Huu Hoang Minh
#include <bits/stdc++.h>
#define sz(x) int(x.size())
#define all(x) x.begin(),x.end()
#define reset(x) memset(x, 0,sizeof(x))
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define N 2005
#define remain(x) if (x > MOD) x -= MOD
#define ii pair<int, int>
#define iiii pair< ii , ii >
#define viiii vector< iiii >
#define vi vector<int>
#define vii vector< ii >
#define bit(x, i) (((x) >> (i)) & 1)
#define Task "test"
#define int long long

using namespace std;

typedef long double ld;
const int inf = 1e10;
const int minf = -1e10;

int t;
int n, m;

void readfile()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);
    if (fopen(Task".inp","r"))
    {
        freopen(Task".inp","r",stdin);
        //freopen(Task".out","w",stdout);
    }
    cin >> t;
}

void solve(){
    cin >> n >> m;
    //1,2,..,m-1,0,1,2,...,m-1,0,1,2,...,y
    int x = n/m;
    int y = n%m;
    int kq = 0;
    //TH1 : 1 <= a < b <= x*m
    //a%m = 0 -> b%m = 0 -> co x*(x-1) cap (ko xet tinh chat a < b)
    kq += x*(x-1);
    //a%m = d -> b%m = m-d -> có x*x cap, co m-1 so
    kq += (m-1)*x*x;
    //if m%2==0 -> loai bo cap trung d = m-d
    if (m%2==0) kq -= x;
    //bo cac cap a > b
    kq /= 2;

    //TH2: 1 <= a <= x*m < b <= y (neu y>0)
    //b%m = d (co y so) -> a%m = m-d  -> moi y so co x cach chon
    if (y) kq += y*x;

    //TH3: m*x <= a < b <= y
    //a%m = d (d < m/2) -> b%m = m-d(m-d > m/2) -> co y-m/2 cach chon
    if (y>m/2) kq += y-m/2;
    cout << kq << '\n';
}

void proc()
{
    while (t--){
        solve();
    }
}

signed main()
{
    readfile();
    proc();
    return 0;
}