/*
        SUPTO
        UNIVERSITY OF DHAKA
*/
#include <bits/stdc++.h>
using namespace std;
#define D(x) cerr<<#x " = "<<(x)<<endl
#define pb push_back
#define ff first
#define ss second
#define mem(a) memset(a,0,sizeof(a))
#define _set(a) memset(a,-1,sizeof(a))
typedef long long int ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
#define eps 1e-9
#define MAX 100000
#define MAXL 20
#define MAXE 100000
#define inf 1000000000
//ll mod = 1000000000+7;
//int dx[] = {0,0,1,-1};
//int dy[] = {1,-1,0,0};
//int dx[] = {-1,-1,-1,0,0,1,1,1};
//int dy[] = {-1,0,1,-1,1,-1,0,1};
pii ar[20];
int main()
{
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
    int ncase, tcase = 1, i, n;
    scanf("%d", &n);
    for(i = 0; i < n; i++) scanf("%d %d", &ar[i].ff, &ar[i].ss);
    for(i = 1; i < n; i++)
    {
        if(ar[0].ff != ar[i].ff) break;
    }
    if(i == n) printf("YES\n");
    else
    {
        for(i = 1; i < n; i++)
        {
            if(ar[i].ss != ar[0].ss) break;
        }
        if(i == n) printf("YES\n");
        else printf("NO\n");
    }
    return 0;
}