#include <bits/stdc++.h> using namespace std; typedef signed long long ll; #define _P(...) (void)printf(__VA_ARGS__) #define FOR(x,to) for(x=0;x<(to);x++) #define FORR(x,arr) for(auto& x:arr) #define FORR2(x,y,arr) for(auto& [x,y]:arr) #define ALL(a) (a.begin()),(a.end()) #define ZERO(a) memset(a,0,sizeof(a)) #define MINUS(a) memset(a,0xff,sizeof(a)) template<class T> bool chmax(T &a, const T &b) { if(a<b){a=b;return 1;}return 0;} template<class T> bool chmin(T &a, const T &b) { if(a>b){a=b;return 1;}return 0;} //------------------------------------------------------- int M; ll A[101010],B[101010],C[101010]; map<ll,vector<int>> V; unordered_map<ll,int> D; void dfs(ll p,int dir) { if(D.count(p)) { if(D[p]!=dir) { cout<<"NO"<<endl; exit(0); } return; } D[p]=dir; ll a=p>>30; ll b=p-(a<<30); D[(b<<30)+a]=dir^1; if(V[p].size()>2) { cout<<"NO"<<endl; exit(0); } FORR(v,V[p]) { if(p==((A[v]<<30)+B[v])||p==((B[v]<<30)+C[v])||p==((C[v]<<30)+A[v])) { dfs((A[v]<<30)+B[v],dir); dfs((B[v]<<30)+C[v],dir); dfs((C[v]<<30)+A[v],dir); } else { dfs((A[v]<<30)+B[v],dir^1); dfs((B[v]<<30)+C[v],dir^1); dfs((C[v]<<30)+A[v],dir^1); } } } void solve() { int i,j,k,l,r,x,y; string s; cin>>M; FOR(i,M) { cin>>A[i]>>B[i]>>C[i]; } FOR(i,M) { V[(A[i]<<30)+B[i]].push_back(i); V[(B[i]<<30)+C[i]].push_back(i); V[(C[i]<<30)+A[i]].push_back(i); V[(A[i]<<30)+C[i]].push_back(i); V[(C[i]<<30)+B[i]].push_back(i); V[(B[i]<<30)+A[i]].push_back(i); } FORR2(a,b,V) if(D.count(a)==0) dfs(a,0); cout<<"YES"<<endl; } int main(int argc,char** argv){ string s;int i; if(argc==1) ios::sync_with_stdio(false), cin.tie(0); FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin); cout.tie(0); solve(); return 0; }