#include<bits/stdc++.h> //_Shaffi
using namespace std;
#define sc scanint
#define sl scanlong
#define gc getchar
typedef unsigned long long ull;

void scanint(int &x);
void scanlong(ull &x);

void scanint(int &x)
{
        int flag=0;
        register int c = gc();
        if(c == '-') flag=1;
	x = 0;
	for(;(c<48 || c>57);c = gc());
	for(;c>47 && c<58;c = gc()) {x = (x<<1) + (x<<3) + c - 48;}
        if(flag == 1)x=-x;
}

void scanlong(ull &x)
{
        int flag=0;
        register int c = gc();
        if(c == '-') flag=1;
	x = 0;
	for(;(c<48 || c>57);c = gc());
	for(;c>47 && c<58;c = gc()) {x = (x<<1) + (x<<3) + c - 48;}
        if(flag == 1)x=-x;
}
int main()
{
    int n,i,j,count=1,flag=0,vount=1,lount=0; sc(n); j=n; vector<pair<int,int> >p;
    for(i=0;i<n;i++)
    {
        int a,b; sc(a); sc(b); p.push_back(make_pair(a,b));
    }
    int m=p[0].first, q=p[0].second;
    for(i=1;i<n;i++)
    {
        if(p[i].first==p[0].first)
            count++;
        if(p[i].second==p[0].second)
            vount++;
    }
    //cout<<count;
    if(count==n||vount==n) cout<<"YES\n";
    else cout<<"NO\n";
}