#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,k,l;
    cin >> n;
    int i,j,x[n],y[n];
    for(i=0;i<n;i++)
        {
        cin>>x[i]>>y[i];
    }
    int sum=0,sum1=0;
    for(i=1;i<n;i++)
        {
        if(x[i]==x[i-1])sum++;
    }
    for(i=1;i<n;i++)
        {
        if(y[i]==y[i-1])sum1++;
    }
    if(sum1==n-1 || sum==n-1)cout<<"YES\n";
    else
        cout<<"NO\n";
    return 0;
}