#include "bits/stdc++.h"
using namespace std;
#define boost ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)

typedef long long ll;
typedef string str;
typedef double db;
typedef long double ld;
typedef pair<int, int> pi;
#define fi first
#define se second

#define pb push_back
#define mp make_pair
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define endl "\n"

#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)

const ll MOD = 1e9 + 7; //998244353
const ll INF = 1e18;
const ll MX = 1e9 + 10;
const int nx[4] = {0, 0, 1, -1}, ny[4] = {1, -1, 0, 0}; //right left down up

#ifndef LOCAL
#define cerr if(false) cerr
#endif
#define debug(x) cerr << #x << " : " << x << endl;
#define debugs(x,y) cerr << #x << " : " << x << " / " << #y << " : " << y << endl;
#define debugv(v) cerr << #v << " : " << "[ "; for(auto it : v) cerr << it << ' '; cerr << ']' << endl;
#define here() cerr << "here" << endl;

void IO() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
}

ll solve(ll n)
{
    return n*(n-1)/2;
}
int main()
{
    boost;
    IO();

    ll n;
    cin >> n;
    vector<ll> arr(n);

    FOR(i, 0, n)
    {
        cin >> arr[i];
        arr[i]%=200;
    }

    vector<ll> vis(200, 0);
    vector<ll> res;

    FOR(i, 0, n)
    {
        vis[arr[i]]++;
    }

    FOR(i, 0, 200)
    {
        if(vis[i]>0)
            res.pb(vis[i]);
    }


    ll sum = 0;
    ll len = res.size();
    FOR(i, 0, len)
    {
        ll temp = res[i];
        sum+=solve(temp);
    }

    cout << sum << endl;

    return 0;
}

#include <bits/stdc++.h>

using namespace std;

#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")

using ll = long long;
using ld = long double;



#define mp make_pair

int p = 1e9 + 7;

int mul(int a, int b) {
    return (1LL * a * b) % p;
}

int add(int a, int b) {
    int s = (a+b);
    if (s>=p) s-=p;
    return s;
}

int sub(int a, int b) {
    int s = (a+p-b);
    if (s>=p) s-=p;
    return s;
}

int po(int a, int deg)
{
    if (deg==0) return 1;
    if (deg%2==1) return mul(a, po(a, deg-1));
    int t = po(a, deg/2);
    return mul(t, t);
}

int inv(int n)
{
    return po(n, p-2);
}


mt19937 rnd(time(0));


const int N = 1000005;

vector<int> facs(N), invfacs(N);

void init()
{
    facs[0] = 1;
    for (int i = 1; i<N; i++) facs[i] = mul(facs[i-1], i);
    invfacs[N-1] = inv(facs[N-1]);
    for (int i = N-2; i>=0; i--) invfacs[i] = mul(invfacs[i+1], i+1);
}

int C(int n, int k)
{
    if (n<k) return 0;
    if (n<0 || k<0) return 0;
    return mul(facs[n], mul(invfacs[k], invfacs[n-k]));
}




/*struct DSU
{
    vector<int> sz;
    vector<int> parent;

    void make_set(int v) {
        parent[v] = v;
        sz[v] = 1;
    }

    int find_set(int v) {
        if (v == parent[v])
            return v;
        return parent[v] = find_set(parent[v]);
    }

    void union_sets(int a, int b) {
        a = find_set(a);
        b = find_set(b);
        if (a != b) {
            if (sz[a] < sz[b])
                swap(a, b);
            parent[b] = a;
            sz[a] += sz[b];
        }
    }

    DSU (int n)
    {
        parent.resize(n);
        sz.resize(n);
        for (int i = 0; i<n; i++) make_set(i);
    }
};*/


int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(nullptr);

    int n; cin>>n;
    string s;
    cin>>s;
    vector<char> a(2e5);
    int cur = 0;
    for (auto c: s)
    {
        a[cur] = c;
        if (cur>=2 && a[cur-2]=='f' && a[cur-1]=='o' && a[cur]=='x') cur-=3;
        cur++;
    }
    cout<<cur;
}

