#include <bits/stdc++.h>
using namespace std;
typedef pair <int, int> pii;
const int MAXN = 1e5 + 5;
const int offset = 1 << 17;
struct Segment {
int x1, y1, x2, y2;
};
class Tournament {
set <pii> S[2 * offset];
public:
void update(int x, int lo, int hi, int from, int to, pii p) {
if (lo >= to || hi <= from)
return;
if (lo >= from && hi <= to) {
S[x].insert(p);
return;
}
int mid = (lo + hi) / 2;
update(2 * x, lo, mid, from, to, p);
update(2 * x + 1, mid, hi, from, to, p);
}
vector <int> query(int x, int from, int to) {
vector <int> res;
for (x += offset; x; x /= 2)
while (1) {
auto it = S[x].lower_bound({from, 0});
if (it == S[x].end() || it->first > to)
break;
res.push_back(it->second);
S[x].erase(it);
}
return res;
}
};
int N;
int x[MAXN], y[MAXN];
vector <int> adj[MAXN];
vector <int> hor[MAXN], ver[MAXN];
vector <Segment> all;
vector <pii> edges;
Tournament Hor, Ver;
int clr[2 * MAXN];
queue <int> Q;
void load() {
scanf("%d", &N);
for (int i = 0; i < N; i++) {
scanf("%d%d", x + i, y + i);
ver[x[i]].push_back(i);
hor[y[i]].push_back(i);
}
}
void bye() {
puts("NE");
exit(0);
}
void process(const vector <int> &v, int c) {
for (auto it : v) {
if (clr[it] == -1)
clr[it] = c;
else if (clr[it] != c)
bye();
Q.push(it);
}
}
void other(int pt, int seg) {
if (adj[pt].size() == 1)
bye();
process({adj[pt][0] ^ adj[pt][1] ^ seg}, 1);
}
void horizontal(int id) {
if (clr[id])
process(Ver.query(all[id].y1, all[id].x1, all[id].x2), 0);
else {
other(edges[id].first, id);
other(edges[id].second, id);
}
}
void vertical(int id) {
if (clr[id])
process(Hor.query(all[id].x1, all[id].y1, all[id].y2), 0);
else {
other(edges[id].first, id);
other(edges[id].second, id);
}
}
inline bool is_hor(int id) {
return all[id].y1 == all[id].y2;
}
void solve() {
memset(clr, -1, sizeof clr);
for (int i = 1; i < MAXN; i++) {
if (hor[i].size() == 2) {
int mn = MAXN, mx = 0;
for (auto it : hor[i]) {
adj[it].push_back(all.size());
mn = min(mn, x[it]);
mx = max(mx, x[it]);
}
Hor.update(1, 0, offset, mn, mx + 1, {i, all.size()});
edges.push_back({hor[i][0], hor[i][1]});
all.push_back({mn, i, mx, i});
}
if (ver[i].size() == 2) {
int mn = MAXN, mx = 0;
for (auto it : ver[i]) {
adj[it].push_back(all.size());
mn = min(mn, y[it]);
mx = max(mx, y[it]);
}
Ver.update(1, 0, offset, mn, mx + 1, {i, all.size()});
edges.push_back({ver[i][0], ver[i][1]});
all.push_back({i, mn, i, mx});
}
}
for (int i = 0; i < N; i++)
if (adj[i].empty())
bye();
else if (adj[i].size() == 1) {
clr[adj[i][0]] = 1;
Q.push(adj[i][0]);
}
while (!Q.empty()) {
int curr = Q.front();
Q.pop();
if (is_hor(curr))
horizontal(curr);
else
vertical(curr);
}
puts("DA");
for (int i = 0; i < all.size(); i++) {
if (clr[i] == -1)
clr[i] = is_hor(i);
if (clr[i])
printf("%d %d\n", ++edges[i].first, ++edges[i].second);
}
}
int main() {
load();
solve();
return 0;
}
