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#include <bits/stdc++.h>
using namespace std;
#define REP(i,a,b) for (int i = (a); i <= (b); ++i)
#define REPD(i,a,b) for (int i = (a); i >= (b); --i)
#define FORI(i,n) REP(i,1,n)
#define FOR(i,n) REP(i,0,int(n)-1)
#define mp make_pair
#define pb push_back
#define pii pair<int,int>
#define vi vector<int>
#define ll long long
#define SZ(x) int((x).size())
#define DBG(v) cerr << #v << " = " << (v) << endl;
#define FOREACH(i,t) for (typeof(t.begin()) i=t.begin(); i!=t.end(); i++)
#define fi first
#define se second

const int N = 500500;
const int M = 1000000;

int n;

int cnt[2][2*M+3];
set<int> vals;

int main() {
	scanf("%d", &n);
	FOR(i,n) {
		int r,w,t;
		scanf("%d%d%d", &r, &w, &t);
		cnt[r-1][w-t+M]++;
		vals.insert(w-t+M);
	}
	int res = 0;
	for (auto v : vals) {
		res += min(cnt[0][v], cnt[1][v]);
	}
	printf("%d\n", res);
	return 0;
}