#include <bits/stdc++.h>
#define ahmed_is_fast \
ios_base::sync_with_stdio(0); \
cin.tie(0); \
cout.tie(0);
#define ll long long
#define ld long double
#define cc(n) cout << n << "\n"
#define ccc(n) cout << n << ' '
#define endl "\n"
#define all(v) v.begin(), v.end()
#define mx(a, b) a = max(a, b)
#define mn(a, b) a = min(a, b)
#define mem(a, b) memset(a, b, sizeof(a))
#define f(a) a.first
#define s(a) a.second
#define lcm(a, b) (a * b) / __gcd(a, b)
#define sp(x) setprecision(x)
using namespace std;
const ll mx=21;
void ahmed()
{
ll n;
cin>>n;
ll x[n+9],y[n+9];
map<ll,ll>mx,my;
for(ll i=0; i<n; i++)
{
cin>>x[i]>>y[i];
mx[x[i]]++;
my[y[i]]++;
}
ll ans=0;
for(ll i=0; i<n; i++)
{
ans += (ll) (mx[x[i]] - 1) * (my[y[i]] - 1);
}
cout<<ans<<endl;
}
bool AHMED = false;
int main()
{
ahmed_is_fast;
ll t = 1;
if (AHMED)
{
cin >> t;
}
while (t--)
{
ahmed();
}
return 0;
}
