#include <bits/stdc++.h>
using namespace std;

#define ll long long int
#define ff first
#define ss second
#define mp make_pair
#define pb push_back

ll arr[100005];
ll brr[100005];

ll ro,co;

ll solve(ll a,ll b,ll x,ll y,ll fol);
vector <pair <int,int> > v;



int main()
{

    int n;
    cin>>n;
   for(int i=0;i<n;i++)
    {
        int a,b;
        cin>>arr[i];
        cin>>brr[i];
    }
    int cnt1=0;
    int cnt2=0;
    for(int i=0;i<n-1;i++)
    {
        if(arr[i]==arr[i+1])
            cnt1++;
        if(brr[i]==brr[i+1])
            cnt2++;
    }
    if(cnt1==n-1||cnt2==n-1)
        cout<<"YES"<<endl;
    else
        cout<<"NO"<<endl;
}