#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    int n;
    cin >> n;
    int X[11], Y[11];
    for(int i = 00; i < n; ++i)
        {
        int x, y;
        cin >> x >> y;
        X[i] = y;
        Y[i] = x;
    }
    int f = 0;
    for(int i = 1; i < n; ++i)
        {
        if(X[i] == X[i - 1])
            ++f;
        else
            break;
    }
    if(f == n)
        {
        puts("YES");
        return 0;
    }
    f = 0;
    for(int i = 1; i < n; ++i)
        {
        if(Y[i] == Y[i - 1])
            ++f;
        else
            break;
    }
    if(f == n)
        {
        puts("YES");
        return 0;
    }
    puts("NO");
    return 0;
}