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#include <bits/stdc++.h>

using namespace std;

#define ALL(x) (x).begin(), (x).end()

template<class C> void mini(C &a5, C b5) { a5 = min(a5, b5); }
template<class C> void maxi(C &a5, C b5) { a5 = max(a5, b5); }

#ifdef LOCAL
const bool debug = true;
#else
const bool debug = false;
#define cerr if (true) {} else cout
#endif

#define int long long
#define double long double

const int INF = 1e18;
const int mod = 1e9 + 7;

const int max_n = 2*(1e6 + 100);

int tab[2][max_n];

int32_t main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    
    int n;
    cin >> n;
    for (int i = 0; i < n; i++) {
		int r, w, t;
		cin >> r >> w >> t;
		r--;
		tab[r][w - t + max_n / 2]++;
	}
	
	int res = 0;
	for (int i = 0; i < max_n; i++) {
		res += min(tab[0][i], tab[1][i]);
	}
	
	cout << res;
    
    return 0;
}/*
4
1 5 2
2 3 0
2 3 6
1 7 4
*/