#include<bits/stdc++.h>
#define el '\n'
#define ll long long
#define N 1000000
using namespace std;
ll n,a[N+3],x;
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);cout.tie(NULL);
    cin>>n; ll ma=-1e10; ll mi=1e10;
    for(ll i=1;i<=n;i++)
    {
        cin>>x;
        a[x]++;
        ma=max(ma,x);
        mi=min(mi,x);
    }
    ll s=0;
    for(ll i=mi;i<=ma;i++)
    {
        if(a[i]!=0 && a[i]>0) {s=s+((a[i]*(a[i]-1))/2);}
    }
    cout << s << el;
}