#include <stdio.h>
#include <stdlib.h>

int main()
{
    int n;
    scanf("%d",&n);
    int i,x[n],y[n],count1=0,count2=0;
    for(i=0;i<n;i++)
       scanf("%d %d",&x[i],&y[i]);

       int b = x[0];
       int c = y[0];
    for(i=0;i<n;i++)
    {
        if(x[i]==b)
            count1++;

    }
     for(i=0;i<n;i++)
    {
        if(y[i]==c)
            count2++;

    }
    if((count1==n)||(count2==n))
        printf("YES\n");
    else
        printf("NO");
    return 0;
}