#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 ct1=1, ct2=1,f1,f2;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        if(a0==0)
            {
            f1=x;
            f2=y;
            
        }
        else 
            {
            if(f1==x)
                ct1++;
            if(f2==y)
                ct2++;
        }
    }
    
    if(ct1==n)
        cout<<"YES"<<endl;
    else if(ct2==n)
        {
        cout<<"YES"<<endl;
    }
    else
        cout<<"NO"<<endl;
        
    
    return 0;
}