#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;


int main(){
    int n;
    cin >> n;
    int firstx;
    int firsty;
    int consta;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        if(a0==0){firstx=x;firsty=y;}
        else if(a0==1){
            if(x==firstx){consta=0;}
            else if(y==firsty){consta=1;}
            else{consta = -1;a0=n;}
        }
        else{
        if(consta ==0 ){if (x!=firstx){consta =-1;a0=n;}}
            if(consta==1 && y!=firsty){consta =-1;a0=n;}
        }
    }
    if(consta!=-1){cout<<"YES";}
    else{cout<<"NO";}
    return 0;
}