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#include <cassert>
#include <cstdint>
#include <algorithm>
#include <iostream>
#include <string>
#include <vector>
#include <unordered_map>

typedef int32_t i32;

struct C {
    i32 c[2];
    C() { c[0] = 0; c[1] = 0; }
};

typedef std::unordered_map<i32, C> Map;

int main()
{
    i32 n;
    std::cin >> n;

    Map M;

    for (i32 i = 0; i < n; i++) {
        i32 r1, w, t;
        std::cin >> r1 >> w >> t;
        i32 k = w - t;
        M[k].c[r1 - 1]++;
    }

    i32 s =  0;
    for (const auto &p : M) {
        auto c = p.second.c;
        if (c[0] > 0 && c[1] > 0)
            s += std::min(c[0], c[1]);
    }

    std::cout << s << '\n';

    return 0;
}