#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

int main()
{
    int n;
    std::vector<ll> v,w ;
    bool ans=false;
    rep(i,n){
        cin>>v[i]>>w[i];
        if(w[i]==1)ans=true;
    }
    cout<<(ans?"Yes":"No")<<endl;
}