#include<cstdio>
#include<iostream>
using namespace std;

int wspA[2000005];
int wspB[2000005];
int maxx = 1000000;
int n, r, w, t;
int wynik, wsp;

int main() {
	ios_base::sync_with_stdio(0);
	cin >> n;
	for (int i = 1; i <= n; i++) {
		cin >> r >> w >> t;
		wsp = maxx + w - t;
		if(r == 1) {
			wspA[wsp]++;
		} else {
			wspB[wsp]++;
		}
	}
	
	for (int i = 0; i <= 2*maxx; i++) {
		wynik += min(wspA[i], wspB[i]);
	}
	
	cout << wynik;
	
	return 0;
}