//Amit Gupta              
#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 200010
#define endl '\n'
#define FILL(ar,vl) for(int i=0;i<N;i++)ar[i]=vl
#define FILL2(ar,vl) for(int i=0;i<N;i++)for(j=0;j<N;j++)ar[i][j]=vl
//--------------------------MAIN CODE STARTS HERE----------------
int main()
{
    int n;
    cin>>n;
    int a[n],b[n];
    REP(i,0,n)
    {
        cin>>a[i]>>b[i];
        
    }
    int f=0;int f1=0;
    REP(i,1,n)
    {
        if(a[i]!=a[i-1])
            f=1;
        if(b[i]!=b[i-1])
            f1=1;
    }
    if(f==1&&f1==1)
        cout<<"NO\n";
    else 
        cout<<"YES\n";


    return 0;
}