#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,arrx[100],arry[100],i,count1=0,count2=0;
    cin >> n;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        arrx[a0]=x;
        arry[a0]=y;
    }
    for(i=0;i<n-1;i++)
        {
        if(arrx[i]==arrx[i+1])count1++;
        if(arry[i]==arry[i+1])count2++;
    }
    if(count1==n-1||count2==n-1)printf("YES\n");
    else printf("NO\n");
    return 0;
}