#include<bits/stdc++.h>//sumu_rainzz
using namespace std;
#define gc getchar
#define mp make_pair
#define pb push_back
#define sc scanint
#define f first
#define s second
#define mi 1000000007
typedef vector<int> vi;
typedef vector<pair<int,int> > vii;
typedef long long ll;
typedef pair<int, int> pii;


void scanint(int &x)
{
    register int c = gc();
    x = 0;
    int neg = 0;
    for(;((c<48 || c>57) && c != '-');c = gc());
    if(c=='-') {neg=1;c=gc();}
    for(;c>47 && c<58;c = gc()) {x = (x<<1) + (x<<3) + c - 48;}
    if(neg) x=-x;
}
int main()
{
int n;
sc(n);
vi arr;
vi arr1;
for(int i=0;i<n;i++)
{
    int a,b;
    sc(a);
    sc(b);
    arr.pb(a);
    arr1.pb(b);



}
if(count(arr.begin(),arr.end(),arr[0])==n||count(arr1.begin(),arr1.end(),arr1[0])==n)
    cout<<"YES"<<endl;
else cout<<"NO"<<endl;


return 0;
}