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#include <bits/stdc++.h>
#define pb push_back
#define fi first
#define se second
#define sz(x) (int)x.size()
#define cat(x) cerr << #x << " = " << x << endl
#define IOS cin.tie(0); ios_base::sync_with_stdio(0)
 
using ll = long long;
using namespace std;

map <int, int> m[2];

int main() {
	int n;
	scanf("%d", &n);
	while (n--) {
		int a, b, c;
		cin >> a >> b >> c;
		m[--a][c - b]++;
	}
	int res = 0;
	for (auto [key, val] : m[0])
		res += min(val, m[1][key]);
	printf("%d\n", res);
	return 0;
}