#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;


int main(){
    int n;
    cin >> n;
    long long a,b;
    
    cin>>a>>b;
    int f1=1,f2=1;
    for(int a0 = 0; a0 < n-1; a0++){
        long long x;
        long long y;
        cin >> x >> y;
        if(a!=x)
            f1=0;
        if(b!=y)
            f2=0;
    }
    if(f2==1 || f1==1)
        printf("YES\n");
    else
        printf("NO\n");
    return 0;
}