#include <bits/stdc++.h>

using namespace std;

#define SZ(x) ((int)(x).size())

struct point {
  int x, y, i;

  void read(int z) {
    scanf("%d%d", &x, &y);
    i = z;
  }

  point operator-(const point& p) const {
    return {p.x - x, p.y - y};
  }

  bool operator<(const point& rhs) const {
    if(x != rhs.x) {
      return x < rhs.x;
    } else {
      return y < rhs.y;
    }
  }
};

int n;

vector<point> P;

long long cross(point a, point b) {
  return 1LL*a.x*b.y - 1LL*a.y*b.x;
}

int main() {
  int foo, bar;
  scanf("%d", &n);
  for(int i = 0; i < n - 1; i++) scanf("%d%d", &foo, &bar);
  P.resize(n);
  for(int i = 0; i < n; i++) P[i].read(i);
  sort(P.begin(), P.end());

  for(int i = 0; i + 1 < n; i++) {
    printf("%d %d\n", P[i].i, P[i+1].i);
  }
  return 0;

  int j = 0;
  for(int i = 0; i < SZ(P); i++) {
    if(P[i].y < P[j].y || 
	(P[i].y == P[j].y && P[i].x > P[j].x)) {
      j = i;
    }
  }

  point a = P[j];
  P.erase(P.begin() + j);

  while(!P.empty()) {
    j = 0;
    for(int i = 1; i < SZ(P); i++) {
      point vi = P[i]-a;
      point vj = P[j]-a;

      if(cross(vi, vj) > 0) {
	j = i;
      }
    }
    printf("%d %d\n", a.i, P[j].i);
    a = P[j];
    P.erase(P.begin() + j);
  }

}