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

int main() {
  ios::sync_with_stdio(false);

  int N;
  cin >> N;

  vector<string> S(N);
  for (int i = 0; i < N; ++i) cin >> S[i];

  vector<int64_t> sn(N + 1);
  for (int i = 1; i <= N; ++i) sn[i] = sn[i - 1] + (int64_t) i * (i + 1) / 2;
  
  function<int64_t(int, int, int)> dfs = [&](int x, int l, int r) {
    if (r <= l) return (int64_t) 0;
    int64_t res = 0;
    for (int i = l; i < r; ++i) {
      if (S[i].size() <= x) res += sn[i - l], res += dfs(x + 1, l, i), l = i + 1;
      else if (S[i][x] != S[l][x]) res += sn[i - l], res += dfs(x + 1, l, i), l = i;
    }
    res += sn[r - l];
    res += dfs(x + 1, l, r);
    return res;
  };
  cout << dfs(0, 0, N) << endl;

  return 0;
}