#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 pre1,pre2,fl1=0,fl2=0;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        if(a0==0)
            {
            pre1=x;
            pre2=y;
        }
        else{
            if(pre1==x && fl1==0)
                {
                
            }
            else fl1=1;
            if(pre2==y && fl2==0)
                {
                
            }
            else fl2=1;
        }
    }
    
    if(fl1==1 && fl2==1)
        {
        cout<<"NO"<<endl;
    }
    else cout<<"YES"<<endl;
    
    return 0;
}