#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,x,count1=0,count2=0,y,curr1,curr2;
    cin >> n;
        cin>>x>>y;
        curr1=x;
        curr2=y;
    for(int a0 = 1; a0 < n; a0++){
       
        cin >> x >> y;
        if(curr1==x)
            count1++;
        if(curr2==y)
            count2++;
            
    }
    if(count1==n-1||count2==n-1)
        cout<<"YES";
    else
        cout<<"NO";
    return 0;
}