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

#define REP(i, n) for (int i = 0; i < (int)n; i++)
#define ST first
#define ND second
#define MP make_pair
#define PB push_back

typedef vector<int> VI;
typedef pair<int, int> PII;
typedef vector<PII> VPII;
typedef set<int> SI;
typedef long long LL;

#ifdef DEBUG
const bool debug = true;
#else
const bool debug = false;
#endif

// #define MULTI_TASK true

const int INF = 1000 * 1000 * 1000;
const LL INFLL = 1e18;
const int MAKSN = 1000 * 1000 + 13;
const LL MOD = 123456789LL;
LL N, M, k, l, a, b, c, d, w, t;
vector<LL> v;

map<LL, LL> m[2];

void zeruj() {
    v.clear();
}


void readIn() {
    cin >> N;
    REP(i, N) {
        cin >> k >> w >> t;
        m[k - 1][w-t]++;
    }
}

void solve() {
    LL res = 0;
    for (auto x: m[0]) {
        LL val = x.ST;
        res += min(m[0][val], m[1][val]);
    }

    cout << res << "\n";
}

int main() {
    ios_base::sync_with_stdio(0);
#ifdef MULTI_TASK
    int test;
    cin >> test;
    while (test--) {
#endif
        zeruj();
        readIn();
        solve();
#ifdef MULTI_TASK
    }
#endif
    return 0;
}