#include <bits/stdc++.h>
using namespace std;
int a[50];
int main() {
  int f = 2, ct[110];
  ct[0] = 0;
  ct[1] = 0;
  ct[2] = 1;
  for (int i = 3; i <= 101; i++) {
    ct[i] = ct[i - 1] + f;
    f++;
  }
  string s;
  int n, m;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> s;
    m = s[0] - 96;
    a[m]++;
  }
  int sum = 0, dis, l;
  for (int i = 1; i <= 26; i++) {
    if (a[i] != 0) {
      dis = a[i] / 2;
      l = a[i] - dis;
      sum += (ct[l] + ct[dis]);
    }
  }
  cout << sum << endl;
  return 0;
}
