#include<stdio.h>
int main()
{
    int a[100],b[100];
    int i,j,n,k;
    int count1=0,count2=0;
    scanf("%d",&n);
    for(i=0;i<n;i++)
    {
        scanf("%d",&a[i]);
        scanf("%d",&b[i]);
        if(i>0)
        {
        if(a[i]==a[i-1])
        {
            count1++;
        }
        if(b[i]==b[i-1])
        {
            count2++;
        }        
        }
    }
    /*if(count1==n-1&&count2==n-1)
    {
        printf("NO");
    }
    else*/
    if(count1==n-1||count2==n-1)
    {
        printf("YES");
    }
    else
        printf("NO");
    return 0;
}