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#include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a); i<(b); ++i)
typedef vector<int> vi;
#define pb push_back
#define sz size()
typedef pair<int,int> pii;
#define mp make_pair
#define st first
#define nd second
typedef long long ll;
#define INF 1000000001
#define ALL(t) t.begin(),t.end()
#define SC(a) scanf("%d", &a)
#define GET(a) int a; SC(a)

#define ISDEBUG 1
#define dprintf(...) if(ISDEBUG) \
{printf("\033[31m"); printf(__VA_ARGS__); printf("\033[0m");}
template <class It> void dptab(It b, It e, const char* f="%d ") {
	if(ISDEBUG) {
		for(It it=b; it!=e; ++it) dprintf(f, *it); dprintf("\n");
}}

int main() {
	map<int, int> occurrences[2];
	GET(n);
	FOR(i,0,n) {
		GET(type);
		GET(x);
		GET(tx);
		--type;
		int id = x-tx;
		if(!occurrences[type].count(id)) {
			occurrences[type][id] = 0;
		}
		occurrences[type][id]++;
	}
	int to_be_deleted = 0;
	for(const auto& id_counter : occurrences[0]) {
		const int& id = id_counter.first;
		const int& count = id_counter.second;
		if(occurrences[1].count(id)) {
			to_be_deleted += min(count, occurrences[1][id]);
		}
	}
	printf("%d\n", to_be_deleted);
	return 0;
}