#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;
    vector<int> xv(n), yv(n);
    int cons =0, idx = 0;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        xv[a0] = x;
        yv[a0] = y;
    }
    for(idx = 0; idx < (n -1); idx++){
        if (xv[idx] == xv[idx+1] || yv[idx] == yv[idx+1]) {
            //cout << "x or y same, now should be same for others" << endl;
            cons++;
        }
    }
    //cout << "cons:" << cons << ":idx:" << idx << endl;
    if (cons) {
        if (cons < idx) {
            cout << "NO" << endl;
        }
        else if (idx == n -1) {
           cout << "YES" << endl;
        }
    }
    else 
       cout << "NO" << endl;
    
    return 0;
}