#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,i,count=0,x,y;
    cin>>n;
    for(i=0;i<n;i++)
        {
        cin>>x>>y;
        if(x==0||y==0)
            {
            count++;
        }
    }
    if(count==n)
        {
        cout<<"YES"<<endl;
    }
    else
        {
        cout<<"NO"<<endl;
    }
    return 0;
}