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

int main(){
    int n,t,*a,*b,i;
    t=1;
    while(t--){
        scanf("%d",&n);
        a = (int*)malloc(n*sizeof(int));
        b = (int*)malloc(n*sizeof(int));
        int marka = 0, markb = 0;
        scanf("%d%d",&a[0],&b[0]);
        scanf("%d%d",&a[1],&b[1]);
        if(a[1]==a[0]){
            marka=1;
        }
        if(b[1]==b[0]){
            markb=1;
        }
        for(i=2;i<n;i++){
            scanf("%d%d",&a[i],&b[i]);
            if(a[i]!=a[i-1]){
                marka=0;
            }
            if(b[i]!=b[i-1]){
                markb=0;
            }
        }
        if(marka==1 || markb==1){
            printf("YES\n");
        }
        else {
            printf("NO\n");
        }
    }
    return 0;
}