#include <iostream>
#include <vector>
using namespace std;
int main()
{
    long long int t,i,z,count=0,summ=0,sumn=0;
    cin>>t;
    vector <long long int> m,n;
    for(i=0;i<t;i++)
    {
        long long int x,y;
        cin>>x>>y;
        m.push_back(x);

        summ=summ+x;
        n.push_back(y);

        sumn=sumn+y;
    }

    z=summ/t;

    for(i=0;i<t;i++)
    {
        if((m[i]>=150)&&(m[i]>=z)&&(m[i]*100/n[i]))
        {
            count++;
        }
    }
    cout<<count;




    return 0;
}