#include <bits/stdc++.h>
using namespace std;

#define rep(i, n) for (int i = 0; i < (int)n; i++)

int main() {
  int N;
  cin >> N;
  vector<string> S(N);
  rep(i, N) cin >> S[i];
  vector<string> T;
  rep(i, N) rep(j, N) {
    if (i == j)
      continue;
    string tmp = S[i] + S[j];
    if (find(T.begin(), T.end(), tmp) == T.end())
      T.push_back(tmp);
  }
  cout << (int)T.size() << endl;
  return 0;
}