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

#define LL long long
#define ULL unsigned long long
#define MOD 1000000007
#define TR(it,container) for(auto it=container.begin();it!=container.end();++it)
#define DB(x) cout<<#x<<"="<<x<<endl;
#define DB2(x,y) cout<<#x<<"="<<x<<" "<<#y<<"="<<y<<endl;
#define DB3(x,y,z) cout<<#x<<"="<<x<<" "<<#y<<"="<<y<<" "<<#z<<"="<<z<<endl;
#define DBA(arr,size) for(auto i=0;i<size;++i) cout<<arr[i]<<" "; cout<<endl;
#define DB2DA(arr,row,col) for(auto i=0;i<row;++i){ for(auto j=0;j<col;++j) cout<<arr[i][j]<<" "; cout<<endl; }
#define FOR(i,x,y) for(auto i=x;i<=y;++i)
#define ROF(i,y,x) for(auto i=y;i>=x;--i)
#define ALL(container) container.begin(),container.end()
#define endl "\n"


int main(){
    ios::sync_with_stdio(false); cin.tie(NULL);
    #ifdef LOCAL_MACHINE
    freopen("input.txt","r",stdin);
    //freopen("output.txt","w",stdout);
    #endif // LOCAL_MACHINE
    int n,x,y,temp;
    cin>>n;
    int arr1[n],arr2[n];
    FOR(i,0,n-1){
        cin>>arr1[i]>>arr2[i];
    }
    sort(arr1,arr1+n);
    sort(arr2,arr2+n);
    if(arr1[0]==arr1[n-1]||arr2[0]==arr2[n-1]) cout<<"YES";
    else cout<<"NO";
}