#include<stdio.h>
int main()
    {
    int i,j,a,b,c,count=0,count1=0;
    scanf("%d",&a);
    int x[a];
    int y[a];
    for(i=0;i<a;i++)
        {
        scanf("%d %d",&x[i],&y[i]); 
      }
    b=x[0];
    c=y[0];
    for(i=1;i<a;i++)
        {
        if(x[i]==b)
            count++;
        if(y[i]==c)
            count1++; 
       }
    if(count+1==a&&count1+1!=a)
        printf("YES");
     else if(count+1!=a&&count1+1==a)
        printf("YES");
    else if(count+1==a&&count1+1==a)
        printf("NO");
    else
        printf("NO");
    return 0;
   
}