#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,a=0,b=0;
    cin >> n;
    int x1,y1;
    cin>>x1>>y1;
    for(int a0 = 0; a0 <n-1; a0++){
        int x;
        int y;
        cin >> x >> y;
        if(x==x1)a++;
        if(y==y1)b++;
        
    }
    if(a==(n-1)||b==(n-1))
        printf("YES");
    else printf("NO");
    return 0;
}