//It's all about what U BELIEVE
#include<iostream>
#include<vector>
#include<cstdint>
#include<algorithm>
#include<stdio.h>
#include<map>
#include<bitset>
#include<stack>
#include<queue>
#include<deque>
#include<tuple>
#include<cstring>
#include<cmath>
#include<unordered_map>
#include<climits>
#include<set>
#include<unordered_set>
#define fo(y , z) for(int y = 0 ; y < z ; y++)
#define ui unsigned int
#define ull unsigned long long
#define pairii pair<int , int>
#define pairull pair<unsigned long long , unsigned long long>
#define seti set<int>
#define setpii set<pairii >
#define setull set<unsigned long long>
#define qint queue<int>
#define dqint deque<int>
#define pb push_back
#define gcu getchar_unlocked
#define modulo 1000000007
#define wtm while(t--)
#define wnm while(n--)
#define non if(!n)break;
#define readf freopen("/home/ebram96/Desktop/in" , "r" , stdin);
#define writef freopen("/home/ebram96/Desktop/out" , "w" , stdout);
using namespace std;
//bool bin(string a , string b){return a > b;}
//bool bina(int a , int b){return a > b;}
bool bin(ull a , ull b){return a > b;}
int main()
{
	//readf
	bool res = 1 , v = 0;
	int n , x , y;
	scanf("%d" , &n);
	while(n--)
	{
		scanf("%d %d" , &x , &y);
		if(!x&&y)
		{
			v = 1;
			break;
		}
		else if(x&&!y)break;
	}
	if(n&&n>0)
	while(n--)
	{
		scanf("%d %d" , &x , &y);
		if(v)
		{
			if(x)
				res = 0;
		}
		else
		{
			if(y)
				res = 0;
		}
	}
	if(res)
		puts("YES");
	else puts("NO");
}