#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(){
    queue<int>q;
    queue<int>q1;
    int n;
    int c=0;
    int d=0;
    cin >> n;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
    if(!q.empty())
        {
        if(q.front()==x)
            c++;
    }else
        q.push(x);
        if(!q1.empty())
            {
            if(q1.front()==y)
                d++;
        }
        else
            q1.push(y);
    }
    if(c==(n-1)  ||  d==(n-1))
        cout<<"YES";
    else
        cout<<"NO";
    return 0;
}