#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;
    int a = -20, b = 20;
    int p = -20, q = 20;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        a = max(a, x);
        b = min(b, x);
        p = max(p, y);
        q = min(q, y);
    }
    if(a == b) cout << "YES" << endl;
    else if (p == q) cout << "YES" << endl;
    else cout << "NO" << endl;
    return 0;
}