#include <bits/stdc++.h>
using namespace std;
//#include<atcoder/all>
//using namespace atcoder;
using ll = long long int;
using ull = unsigned long long int;
using ld = long double;
constexpr ll MAX = 2000000000000000000;
constexpr ld PI = 3.14159265358979;
constexpr ll MOD = 0;//2024948111;
ld dotorad(ld K){ return PI * K / 180.0; }
ld radtodo(ld K){ return K * 180.0 / PI; }
mt19937 mt;
void randinit(){ srand((unsigned)time(NULL));mt = mt19937(rand()); }
int main(){
    ll N;
    cin >> N;
    vector<string> S(N);
    for(int i = 0;i < N;i++){
        cin >> S[i];
    }
    set<string> st;
    for(ll i = 0;i < N;i++){
        for(ll j = 0;j < N;j++){
            if(S[i] == S[j]) continue;
            string T = S[i] + S[j];
            st.emplace(T);
        }
    }
    cout << st.size() << endl;
}