#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]; int D[101010]; map<ll,vector<pair<int,int>>> V; void dfs(int p,int dir) { if(D[p]!=-1) { if(D[p]!=dir) { cout<<"NO"<<endl; exit(0); } return; } D[p]=dir; vector<ll> X={((A[p]<<30)+B[p]),((B[p]<<30)+C[p]),((C[p]<<30)+A[p])}; vector<ll> Y={((A[p]<<30)+C[p]),((C[p]<<30)+B[p]),((B[p]<<30)+A[p])}; FORR(a,X) { if(V[a].size()>2) { cout<<"NO"<<endl; exit(0); } FORR2(v,d,V[a]) if(v!=p) dfs(v,dir^1^d); } FORR(a,Y) { if(V[a].size()>2) { cout<<"NO"<<endl; exit(0); } FORR2(v,d,V[a]) if(v!=p) dfs(v,dir^0^d); } } void solve() { int i,j,k,l,r,x,y; string s; cin>>M; FOR(i,M) { cin>>A[i]>>B[i]>>C[i]; V[(A[i]<<30)+B[i]].push_back({i,0}); V[(B[i]<<30)+C[i]].push_back({i,0}); V[(C[i]<<30)+A[i]].push_back({i,0}); V[(A[i]<<30)+C[i]].push_back({i,1}); V[(C[i]<<30)+B[i]].push_back({i,1}); V[(B[i]<<30)+A[i]].push_back({i,1}); } MINUS(D); FOR(i,M) if(D[i]==-1) dfs(i,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; }