#include<bits/stdc++.h>

using namespace std;

#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define all(x) x.begin(),x.end()
#define sz(x) ((int)x.size())
#define eps 1e-9

const int MOD = 1e9+7;

typedef long long ll;
typedef pair<int,int> pii;

ll POWER[65];
ll power(ll a, ll b) {ll ret=1;while(b) {if(b&1) ret*=a;a*=a;if(ret>=MOD) ret%=MOD;if(a>=MOD) a%=MOD;b>>=1;}return ret;}
ll inv(ll x) {return power(x,MOD-2);}

void precompute() {
	POWER[0]=1;
	for(int i=1;i<63;i++) POWER[i]=POWER[i-1]<<1LL;
}

int main() {
//	freopen("TASK.in","r",stdin);	
//	freopen("TASK.out","w",stdout);
	precompute();
	int n;
	cin>>n;
	int x,y;
	cin>>x>>y;
	bool X=true,Y=true;
	for(int i=2;i<=n;i++) {
		int xx,yy;
		cin>>xx>>yy;
		if(yy!=y) Y=false;
		if(xx!=x) X=false;
	}
	if(X or Y) cout<<"YES\n";
	else cout<<"NO\n";
	return 0;
}