#include <bits/stdc++.h>

using namespace std;
int t1[20000100], t2[2000100],k;
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n;
    cin>>n;
    for(int i=0; i<n; ++i)
    {
        int a,b,c;
        cin>>a>>b>>c;
        if(a==1)
        {
            t1[(b-c)+1000000]++;
        }
        else
        {
            t2[(b-c)+1000000]++;
        }
    }
    for(int i=0; i<=2000000; ++i)
    {
        k+=min(t1[i],t2[i]);
    }
    cout<<k;
    return 0;
}