#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 xE,yE;
    int x;
    int y;
    bool bX=true;
    bool bY=true;
    cin>>x>>y;
    xE=x;
    yE=y;
    for(int a0 = 1; a0 < n; a0++){
        cin >> x >> y;
        if(xE!=x)
            bX=false;
        if(yE!=y)
            bY=false;
        
        xE=x;
        yE=y;
    }
    if(bX || bY)
        cout<<"YES";
    else
        cout<<"NO";
}