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#define pb push_back
#define mp make_pair
#define fi first
#define se second 
#define all(...) begin(__VA_ARGS__) , end(__VA_ARGS__)
#define boost {ios_base::sync_with_stdio(false); cin.tie(); cout.tie();}

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef vector <int> vi;
typedef pair<int,int> PII;
typedef pair<ll,ll> PLL;
constexpr ll nax = 5e5+6969, INF = 2e9+6969;

int n,t[3][nax],R,C;
unordered_map<int,int> mr,mc;
vi row, col;

int main()
{
	scanf("%d", &n);
	for(int i=0;i<n;++i)
	{
		for(int j=0;j<3;++j) scanf("%d", &t[j][i]);
		int tmp = t[1][i] - t[2][i];
		if(t[0][i] == 1)
		{
			mr[tmp]++;
			R++;
		}
		else
		{
			mc[tmp]++;
			C++;
		}
	}
	int ans = 0;
	for(auto e: mc)
	{
		if(mr.find(e.fi) == mr.end()) continue;
		ans += min(mr[e.fi], e.se);
	}
	printf("%d\n", ans);
	return 0;
}