#include<bits/stdc++.h> namespace { #pragma GCC diagnostic ignored "-Wunused-function" #include<atcoder/all> #pragma GCC diagnostic warning "-Wunused-function" using namespace std; using namespace atcoder; #define rep(i,n) for(int i = 0; i < (int)(n); i++) #define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--) #define all(x) begin(x), end(x) #define rall(x) rbegin(x), rend(x) template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; } template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; } using ll = long long; using P = pair<int,int>; using VI = vector<int>; using VVI = vector<VI>; using VL = vector<ll>; using VVL = vector<VL>; } int main() { ios::sync_with_stdio(false); cin.tie(0); int n; cin >> n; bool ok = true; dsu uf(2 * n); map<P, P> mp; rep(i, n) { int a, b, c; cin >> a >> b >> c; for (auto [u, v] : {pair(a, b), {b, c}, {c, a}}) { int ni = i; if (u > v) ni = ~ni, swap(u, v); auto [it, inserted] = mp.emplace(pair(u, v), pair(ni, 1)); if (inserted) continue; if (it->second.second >= 2) { ok = false; break; } it->second.second++; int j = it->second.first; bool diff = (ni < 0) ^ (j < 0); if (j < 0) j = ~j; if (diff) uf.merge(i, j), uf.merge(i + n, j + n); else uf.merge(i, j + n), uf.merge(i + n, j); } } bool ans = ok; rep(i, n) ans &= !uf.same(i, n + i); cout << (ans ? "YES\n" : "NO\n"); }