#include <bits/stdc++.h>
#define mp make_pair
#define debug(x) cout << #x << ": " << x << endl
#define pb push_back
typedef long long LL;
const int maxn = 4e5 + 10;
const int inf = 0x3f3f3f3f;
const LL INF = 0x3f3f3f3f3f3f3f3f;
using namespace std;
typedef pair<int, int> p;
p e[maxn], tail[maxn];
int val[maxn], len = 0, n, t, ord[maxn], vis[maxn], tot = 0, head[maxn], to[maxn], tots;
vector<int> g[maxn];
void dfs(int x, int pre) {vis[x] = true;for (int i = 0; i < g[x].size(); ++i) {int v = to[g[x][i]];if (!vis[v]) {tail[tot] = mp(g[x][i] / 2 + 1, v);dfs(v, x);}}
}
int main() {ios::sync_with_stdio(0);cin.tie(0);cin >> t;while (t--) {cin >> n;len = 0;tot = 0;tots = 0;for (int i = 0; i < n; ++i) {cin >> e[i].first >> e[i].second;val[len++] = e[i].first;val[len++] = e[i].second;}sort(val, val + len);len = unique(val, val + len) - val;for (int i = 0; i < len; ++i) {vis[i] = 0;g[i].clear();}for (int i = 0; i < n; ++i) {int fu = lower_bound(val, val + len, e[i].first) - val;ord[fu] = e[i].first;e[i].first = fu;fu = lower_bound(val, val + len, e[i].second) - val;ord[fu] = e[i].second;e[i].second = fu;to[tots] = e[i].second;g[e[i].first].pb(tots++);to[tots] = e[i].first;g[e[i].second].pb(tots++);}/*for (int i = 0; i < tots; ++i)cout << to[i] << endl;*/for (int i = 0; i < len; ++i) {if (!vis[i]) {++tot;head[tot] = i;dfs(i, -1);}}cout << tot - 1 << "\n";for (int i = 1; i < tot; ++i) {cout << tail[i].first  << " " << ord[tail[i].second] << " " << ord[head[i + 1]] << "\n";}}
}