unghidrept

#include <bits/stdc++.h>
namespace FastRead
{
    const int Dim(1e5);
    char buff[Dim];
    int pos,len;
    inline char nc()
    {
        if (pos==len)
        {
            pos=0;
            len=fread(buff,1,Dim,stdin);
            if(!len)
                return EOF;
        }
        return buff[pos++];
    }

    template<class T> inline void Read(T& x) {
        char ch;
        int sgn(1);
        while(!isdigit(ch=nc()))
            if(ch=='-')
                sgn=-1;
        x=ch-'0';
        while(isdigit(ch=nc()))
            x=x*10+(ch-'0');
        x*=sgn;
    }
}

using namespace FastRead;
using namespace std;
vector<int> f,cx,cy,freqx,freqy;
unordered_map<int,int> hx,hy;
vector<pair<int,int>> v;
int n,ix,iy,x,y;
long long res;

inline int Find(const int& x)
{
    return (x==f[x])?x:(f[x]=Find(f[x]));
}

int32_t main()
{
    Read(n);
    v.resize(n);
    for(pair<int, int>&P:v)
    {
        Read(P.first),Read(P.second);
        cx.emplace_back(P.first);
        cy.emplace_back(P.second);
    }
    sort(cx.begin(),cx.end());
    cx.erase(unique(cx.begin(),cx.end()),cx.end());
    for(const int& x:cx)
        hx[x]=++ix;
    sort(cy.begin(),cy.end());
    cy.erase(unique(cy.begin(),cy.end()),cy.end());
    for(const int& y:cy)
        hy[y]=++iy;
    f=freqx =freqy=vector<int>(ix+iy+1);
    for(int i=1;i<=ix+iy;++i)
        f[i]=i;
    for(const pair<int,int>& P:v)
    {
        x=hx[P.first];
        y=hy[P.second]+ix;
        f[Find(x)]=Find(y);
    }
    for(int i=1;i<=ix;++i)
        ++freqx[Find(i)];
    for(int i=ix+1;i<=ix+iy;++i)
        ++freqy[Find(i)];
    res=-n;
    for(int i=1;i<=ix+iy;++i)
        res+=1LL*freqx[i]*freqy[i];
    cout<<res;
    return 0;
}