#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[10], y[10], count=0;
    bool flag;
    cin >> n;

    for(int i = 0; i < n; i++){
        cin >> x[i] >> y[i];
    }

    for(int i = 1; i <= n; i++){
    if(x[i]==x[i-1] || y[i]==y[i-1]) {
        if(x[i]==x[i-1] && y[i]==y[i-1]) count++;
        flag=true;
            continue;
    }
        else { 
            flag=false;
            cout << "NO"<<endl;
            break;
        }
    }
    if(flag)
    (count==n) ? cout << "NO"<<endl : cout << "YES"<<endl;
    return 0;
}