#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;

const int Maxn = 12;

int n;
int x[Maxn], y[Maxn];

int main(){
    cin >> n;
    bool X = true, Y = true;
    for(int a0 = 0; a0 < n; a0++){
        cin >> x[a0] >> y[a0];
        if (x[a0] != x[0]) X = false;
        if (y[a0] != y[0]) Y = false;
    }
    printf("%s\n", X || Y? "YES": "NO");
    return 0;
}