#include <iostream>
#include <string>
#include <vector>
#include <algorithm>

using std::cin, std::cout, std::endl;
using std::string;
using std::vector, std::sort;
using LL = long long;
using namespace std;

const char endq = '\n';

class Rect;
void combineTwoRect(const Rect &rect1, const Rect &rect2, Rect res[]);

class Rect
{
public:
    int width = 0;
    int length = 0;

    // constructor
    Rect(int x, int y)
    {
        if (x > y)
        {
            length = x;
            width = y;
        }
        else
        {
            length = y;
            width = x;
        }
    }

    Rect()
    {
        ;
    }

    bool check(const Rect &rect1, const Rect &rect2)
    {
        // cout << "DEBUG:" << endl;
        // cout << rect1 << endl;
        // cout << rect2 << endl;
        // if one of the edge is greater then the length
        // then it would be impossible
        int maxEdge = max({rect1.length,
                           rect1.width,
                           rect2.length,
                           rect2.width});

        if (maxEdge > length)
        {
            return false;
        }

        Rect rectList[4];

        combineTwoRect(rect1, rect2, rectList);

        for (int i = 0; i < 4; ++i)
        {
            if (canContain(rectList[i]))
            {
                return true;
            }
        }

        return false;
    }

    bool canContain(Rect &rect)
    {
        return (length >= rect.length && width >= rect.width);
    }

    bool operator<(const Rect &anoRect)
    {
        if (length != anoRect.length)
        {
            return length > anoRect.length;
        }
        return width > anoRect.width;
    }

    friend ostream &operator<<(ostream &os, const Rect &rect)
    {
        os << "<Rect: L: " << rect.length << "  W:" << rect.width << ">";
        return os;
    }
};

// ostream &operator<<(ostream &os, const Rect &rect)
// {
//     os << "<Rect: L: " << rect.length << "  W:" << rect.width << ">";
//     return os;
// }

// return a list contains 4 rect
void combineTwoRect(const Rect &rect1, const Rect &rect2, Rect res[])
{
    res[0] = Rect(rect1.length + rect2.length, max(rect1.width, rect2.width));
    res[1] = Rect(rect1.length + rect2.width, max(rect1.width, rect2.length));
    res[2] = Rect(rect1.width + rect2.length, max(rect1.length, rect2.width));
    res[3] = Rect(rect1.width + rect2.width, max(rect1.length, rect2.length));
}

int main()
{
    int count;
    cin >> count;

    int tmp1, tmp2;

    vector<Rect> rectList;

    for (int i = 0; i < count; ++i)
    {
        cin >> tmp1 >> tmp2;
        rectList.push_back(Rect(tmp1, tmp2));
    }

    sort(rectList.begin(), rectList.end());

    // for (auto x : rectList)
    // {
    //     cout << x << endl;
    // }

    long long availableCombine = 0;

    for (int i = 0; i < count - 2; ++i)
    {
        for (int j = i + 1; j < count - 1; ++j)
        {
            for (int k = j + 1; k < count; ++k)
            {
                if (rectList[i].check(rectList[j], rectList[k]))
                {
                    ++availableCombine;
                }
            }
        }
    }

    cout << availableCombine;
    return 0;
}