#include<stdio.h>
#include<algorithm>
using namespace std;
int main()
    {
    int n,i,x[20],y[20];
    scanf("%d",&n);
    for(i=0;i<n;i++)
        {
        scanf("%d",&x[i]);
        scanf("%d",&y[i]);
    }
    i=0;
    int count1=0,count2=0;
    while(i<n-1)
        {
        if(x[i]==x[i+1])
            {
                i++;
                count1++;
            }
        else
            break;
    }
    i=0;
        while(i<n-1)
        {
        if(y[i]==y[i+1])
            {
                i++;
                count2++;
            }
        else
            break;
    }
    if((count1==n-1)||(count2==n-1))
    {
        printf("YES");   
    }
    else
        printf("NO");
    return 0;
}