#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 a,b,f=0,  c=1,d=1;
   
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        if(f=0){f=1;}            
        else{
            if(a==x )
                c++;
            if(b==y)
                d++;
            
        }
        a=x;b=y;
        
    }
    if(c==n || d==n)
        cout<<"YES";
    else
        cout<<"NO";
    return 0;
}