#include <bits/stdc++.h>
using namespace std ;

#define ft first
#define sd second
#define pb push_back
#define all(x) x.begin(),x.end()

#define ull unsigned long long int
#define ui unsigned int
#define ll long long int
#define vi vector<int>
#define vii vector<pair<int,int> >
#define pii pair<int,int>
#define vl vector<ll>
#define vll vector<pair<ll,ll> >
#define pll pair<ll,ll>
#define mp make_pair

#define sc(x) scanf("%d",&x)
#define sc2(x,y) scanf("%d%d",&x,&y)
#define sc3(x,y,z) scanf("%d%d%d",&x,&y,&z)

#define scll1(x) scanf("%lld",&x)
#define scll2(x,y) scanf("%lld%lld",&x,&y)
#define scll3(x,y,z) scanf("%lld%lld%lld",&x,&y,&z)

#define pr1(x) printf("%d\n",x)
#define pr2(x,y) printf("%d %d\n",x,y)
#define pr3(x,y,z) printf("%d %d %d\n",x,y,z)

#define prll1(x) printf("%lld\n",x)
#define prll2(x,y) printf("%lld %lld\n",x,y)
#define prll3(x,y,z) printf("%lld %lld %lld\n",x,y,z)

#define pr_vec(v) for(int i=0;i<v.size();i++) cout << v[i] << " " ;

#define f_in(st) freopen(st,"r",stdin)
#define f_out(st) freopen(st,"w",stdout)

#define fr(i, a, b) for(i=a; i<=b; i++)
#define fb(i, a, b) for(i=a; i>=b; i--)

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define debug( s ) cout << s << "\n"


const int maxn = 1e5 + 10;
const int mod = 1e9 + 7;


int main()
{
    ll n;
    scll1(n);
    ll i,a[n],b[n];
    fr(i,0,n-1)
    {
        scll1(a[i]);
        scll1(b[i]);
    }
    ll x=a[0],y=b[0];
    ll flag1=1,flag2=1;
    fr(i,1,n-1)
    {
        if(a[i]!=x)
            flag1=0;
        if(b[i]!=y)
            flag2=0;
    }
    if(flag1==0&&flag2==0)
        printf("NO\n");
    else
        printf("YES\n");
}