#include <bits/stdc++.h> #include <atcoder/all> using namespace std; using namespace atcoder; //using mint = modint1000000007; //const int mod = 1000000007; //using mint = modint998244353; //const int mod = 998244353; //const int INF = 1e9; //const long long LINF = 1e18; #define rep(i, n) for (int i = 0; i < (n); ++i) #define rep2(i,l,r)for(int i=(l);i<(r);++i) #define rrep(i, n) for (int i = (n) - 1; i >= 0; --i) #define rrep2(i,l,r)for(int i=(r) - 1;i>=(l);--i) #define all(x) (x).begin(),(x).end() #define allR(x) (x).rbegin(),(x).rend() #define P pair<int,int> template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; } template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); 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 _ : { pair(a, b), pair(b, c), pair(c, a) }) { int ni = i; auto[u, v] = _; 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"); return 0; }