#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef pair<int,int> II;
#define REP(i,i1,n) for(int i=i1;i<n;i++)
#define REPB(i,i1,n) for(int i=i1;i>=n;i--)
#define PB push_back
#define MP make_pair
#define ALL(c) (c).begin(),(c).end()
#define F first
#define S second
#define SZ(a) (LL)a.size()
#define EPS 1e-12
#define MOD 1000000007
#define TR1(x) cerr<<#x<<" : "<<x<<endl
#define TR2(x,y) cerr<<#x<<" : "<<x<<" | "<<#y<<" : "<<y<<endl
#define FAST_IO ios_base::sync_with_stdio(false);cin.tie(NULL)
#define SI(c) scanf("%d",&c)
#define SII(c,d) scanf("%d%d",&c,&d)
#define SLL(c) scanf("%lld",&c)
#define PIN(c) printf("%d\n",c)
#define PLLN(c) printf("%lld\n",c)
#define N 10000010
#define INIT1(array,ST,END,val) for(int i=ST;i<END;i++)array[i]=val
#define INIT2(array,nn,mm,val) for(int i=0;i<nn;i++)for(j=0;j<mm;j++)array[i][j]=val

int main()
{
	int n,a[20],b[20];
	int count=1;
	cin>>n;
	REP(i,0,n)
	{
		cin>>a[i]>>b[i];
//		if(a[i]==a[i+1]||b[i]==b[i+1])count++;
	}
	REP(i,0,n-1)
	{
		if(a[i]==a[i+1]||b[i]==b[i+1])count++;
	}	
	
	
	if(count==n)
	{
		cout<<"YES\n";
	}
	else
		cout<<"NO\n";
	return 0;
}