#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;
    int flagx = 1;
    int flagy = 1;
    int testx;
    int testy;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        
        
        if(a0>0){
        
        if(testx!=x)
            flagx=0;
        if(testy!=y)
           flagy = 0;
        }
        testx=x;
        testy=y;
         if(flagx == 0 and flagy==0)
            break;
    }
    if(flagx==1 || flagy==1)
        cout<<"YES\n";
    else
        cout<<"NO\n";
    return 0;
}