#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(){
    long long int n,x,y,f1 = 1 ,f2 = 1,x1,y1;
    cin >> n;
    cin >> x1 >> y1;
    for(long long a0 = 1; a0 < n; a0++){
        cin >> x >> y;
        if(x != x1) f1 = 0;
        if(y != y1) f2 = 0;
        x1 = x;
        y1 = y;
    }
    if(f1 == 0 && f2 == 0) puts("NO");
    else if ( f1 ==0 || f2 == 0) puts("YES");
    else puts("NO");
    
}