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#include <bits/stdc++.h>
#define boost                                                                  \
  ios_base::sync_with_stdio(0);                                                \
  cin.tie(0);                                                                  \
  cout.tie(0)
#define debug(x) cerr << #x << " " << x << endl
#define ll long long
#define st first
#define nd second
using namespace std;
const int N(1e6 + 13);

map<int, int> cars[3];
int n, r, w, t, res;

int main() {
  boost;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> r >> w >> t;
    cars[r][w - t]++;
  }

  for (auto it : cars[1]) {
    res += min(it.nd, cars[2][it.st]);
  }

  cout << res << endl;
}