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#include <iostream>
#include <map>

#ifdef HOME_
    #define DEBUG(x) x
#else
    #define DEBUG(x)
#endif
#define REP(x,n) for(int x=0;x<(n);++x)

using namespace std;

map<int, int> vert, horz;

int n;
int r,w,t;

int main() {
	ios_base::sync_with_stdio(0);
	cin>>n;
	REP(x,n) {
		cin>>r>>w>>t;
		if (r==1)
			++vert[t-w];
		else
			++horz[t-w];
	}
	int wyn = 0;
	auto i1 = vert.begin(), i2 = horz.begin();
	while (i1 != vert.end() && i2 != horz.end()) {
		if (i1->first < i2->first)
			++i1;
		else if (i2->first < i1->first)
			++i2;
		else {
			DEBUG(
				cerr << "kolizja na " << i1->first << "; " << i1->second << " vs " << i2->second << endl;
			)
			wyn += min(i1->second, i2->second);
			++i1;
			++i2;
		}
	}
	cout << wyn;
	return 0;
}