#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,y,first,second,ctr1=0,ctr2=0;
    cin>>n;
    for(int i=0 ; i<n ; i++){
        cin>>x>>y;
        if(i==0){
            first=x;
            second=y;
        }
        else if(first!=x && second!=y)
            break;
        else if(first==x)
            ctr1++;
        else if(second==y)
            ctr2++;
    }
    if(ctr1==n-1 || ctr2==n-1)
        cout<<"YES"<<endl;
    else
        cout<<"NO"<<endl;
    return 0;
}