#include <bits/stdc++.h>
using namespace std;
#define ff first
#define ss second
#define pb push_back
#define int long long
signed main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
int m = 2 * n;
vector<int> id(m), ot(m), cnt(m, 0), used(n, 0);
for (int i = 0; i < n; i++) {
int l, r;
cin >> l >> r;
id[l] = id[r] = i;
ot[l] = r;
ot[r] = l;
int s = (l + r) % m;
if (s & 1) cnt[s]++;
}
pair<int,int> mx = {-1, 1}; // {count, D}
for (int d = 1; d < m; d += 2) {
if (cnt[d] > mx.ff) mx = {cnt[d], d};
}
int D = mx.ss;
cout << n - mx.ff << '\n';
auto tgt = [&](int x) {
int y = (D - x) % m;
if (y < 0) y += m;
return y;
};
for (int i = 0; i < m; i++) {
int s = id[i];
if (used[s]) continue;
int j = ot[i];
if ((i + j) % m == D) {
used[s] = 1;
continue;
}
int p = i;
while (!used[id[p]]) {
int cur = id[p];
int q = ot[p];
int e = tgt(q);
cout << cur << " " << p << " " << e << '\n';
used[cur] = 1;
p = e;
}
}
return 0;
}
