#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,x,y,t1,t2,f1,f2;
    cin >> n;
    cin >> x >> y;
    t1=x;
    t2=y;
    f1=0;
    f2=0;
    for(int a0 = 1; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        if(x!=t1)
            f1=1;
        if(y!=t2)
            f2=1;
    }
    if(f1==0||f2==0)
        printf("YES");
    else
        printf("NO");
    return 0;
}