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