#include<bits/stdc++.h>
using namespace std;
const int N=5e5+5;
struct node{double x,y;int id;}p[N];
bool cmp(node p1,node p2){if(p1.x!=p2.x)return p1.x<p2.x;else return p1.y<p2.y;}
double dis(node p1,node p2){return sqrt((p1.x-p2.x)*(p1.x-p2.x)+(p1.y-p2.y)*(p1.y-p2.y));}
int x,y;
double ans;
void solve(int l, int r)
{
    if (l == r) return ;
    int mid = (l + r) >> 1;
    solve(l,mid);
    solve(mid+1, r);
    int tl = mid, tr = mid;
    while (tl >= l && p[mid].x - p[tl].x < ans) tl--; tl++;
    while (tr <= r && p[tr].x - p[mid].x < ans) tr++; tr--;
    for (int i = tl; i < tr; i++)
        for (int j = i + 1; j <= tr; j++)
        {
            double tmp = dis(p[i], p[j]);
            if (tmp < ans)
            {
                ans = tmp;
                x = p[i].id; y = p[j].id;
            }
        }
}
int main()
{
    int T;scanf("%d",&T);
    while(T--)  {
        int n;scanf("%d",&n);
        for(int i=1;i<=n;i++)scanf("%lf%lf",&p[i].x,&p[i].y),p[i].id=i;
        sort(p+1,p+n+1,cmp);
        ans=1e18;
        solve(1,n);
        printf("%d %d\n",x-1,y-1);
    }
    return 0;
}