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#include <bits/stdc++.h>
const int DELTA = 1500005;
using namespace std;
int n, a, b, c, res;
int t[3][2 * DELTA + 5];
int main() {
	ios_base::sync_with_stdio(0);
	cin >> n;
	for(int i = 1; i <= n; i++) {
		cin >> a >> b >> c;
		t[a][DELTA + b - c]++;
	}

	for(int i = 0; i < 2 * DELTA; i++) res += min(t[1][i], t[2][i]);

	cout << res;
}