#include <bits/stdc++.h>
#define st first
#define nd second
using namespace std;
map<int, int> M1, M2;

int main()
{
    ios_base::sync_with_stdio(0);
    int n;
    cin>>n;
    for(int i=1; i<=n; ++i){
        int type, w, time;
        cin>>type>>w>>time;
        if(type==1){
            M1[w-time]++;
        }
        else{
            M2[w-time]++;
        }
    }
    int ans=0;
    for(auto it=M1.begin(); it!=M1.end(); it++){
        int w=it->st;
        ans+=min(M1[w], M2[w]);
    }
    cout<<ans;
    return 0;
}