#pragma region header
// #pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
#define all(a) begin(a), end(a)
#define rall(a) rbegin(a), rend(a)
#define mp make_pair
#define mt make_tuple
#define rep1(i, n) for (decltype(+n) i = 0; i < (n); i++)
#define rrep1(i, n) for (auto i = n - 1; i > static_cast<decltype(i)>(-1); i--)
#define rep2(i, a, b) for (auto i = (a); i < (b); i++)
#define rrep2(i, a, b) for (auto i = b - 1; i >= a; i--)
#define GET_MACRO(_1, _2, _3, NAME, ...) NAME
#define rep(...) GET_MACRO(__VA_ARGS__, rep2, rep1) (__VA_ARGS__)
#define rrep(...) GET_MACRO(__VA_ARGS__, rrep2, rrep1) (__VA_ARGS__)
#define each(i, a) for (auto &&i : (a))
using namespace std;

using ld = long double;
using vi = vector<int>;
using vvi = vector<vi>;
using vs = vector<string>;
using vvs = vector<vs>;
using vd = vector<ld>;
using vvd = vector<vd>;
using vb = vector<bool>;
using vvb = vector<vb>;
using pii = pair<int, int>;
using vp = vector<pii>;
using vvp = vector<vp>;
using mii = map<int, int>;
using vm = vector<mii>;
using vvm = vector<vm>;
template <class T, class U>
using umap = unordered_map<T, U>;
using umii = umap<int, int>;
using seti = set<int>;
template <class T>
using uset = unordered_set<T>;
using useti = uset<int>;
template <class T>
using less_queue = priority_queue<T>;
template <class T>
using greater_queue = priority_queue<T, vector<T>, greater<T>>;

template <class T>
void SORT(T &a) { stable_sort(all(a)); }
template <class T>
void RSORT(T &a) { stable_sort(rall(a)); }
template <class T>
void rev(T &a) { reverse(rall(a)); }
template <class T>
void uniq(T &a) { a.erase(unique(all(a)), end(a)); }
template <class T>
auto min_of(T a) { return *min_element(all(a)); }
template <class T>
auto max_of(T a) { return *max_element(all(a)); }
template <class T>
int sum_of(T a) { return accumulate(all(a), 0ll); }
template <class T, class U>
auto sum_of(T a, U init) { return accumulate(all(a), init); }
template <class T, class U>
int count_of(T a, U i) { return count(all(a), i); }
template <class T, class U>
bool has(T a, U i) { return find(all(a), i) != end(a); }
template <class T>
int sz(T a) { return a.size(); };

template <class T>
void COUT(T x) { cout << x << endl; }
template <class T, class U>
void COUT(T x, U y) { cout << x << ' ' << y << endl; }
template <class T, class U, class V>
void COUT(T x, U y, V z) { cout << x << ' ' << y << ' ' << z << endl; }
template <class T>
void CSP(T x) { cout << x << ' '; }
template <class T>
void CVEC(T v) {
  int c = v.size() - 1;
  for (int i = 0; i < c; i++) cout << v[i] << ' ';
  if (c > -1) cout << v[c];
  cout << endl;
}

template <class T>
bool amin(T &a, const T &b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
bool amax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}

constexpr int lshift(int x) noexcept { return 1ll << x; }
constexpr int popcount(unsigned int x) noexcept { return __builtin_popcountll(x); }
constexpr int least1(unsigned int x) noexcept { return __builtin_ffsll(x); }
constexpr int ceil_div(int x, int y) noexcept { return (x - 1) / y + 1; }

#pragma endregion header

template <int char_size>
struct trie_node {
  int nxt[char_size];

  int exist;
  vector<int> accept;

  trie_node() : exist(0) {
    memset(nxt, -1, sizeof(nxt));
  }
};

template <int char_size, int margin>
struct trie_tree {
  using Node = trie_node<char_size>;

  vector<Node> nodes;
  int root;

  trie_tree() : root(0) {
    nodes.push_back(Node());
  }

  void update_direct(int node, int id) {
    nodes[node].accept.push_back(id);
  }

  void update_child(int node, int child, int id) {
    ++nodes[node].exist;
  }

  void add(const string &str, int str_index, int node_index, int id) {
    if (str_index == str.size()) {
      update_direct(node_index, id);
    } else {
      const int c = str[str_index] - margin;
      if (nodes[node_index].nxt[c] == -1) {
        nodes[node_index].nxt[c] = (int)nodes.size();
        nodes.push_back(Node());
      }
      add(str, str_index + 1, nodes[node_index].nxt[c], id);
      update_child(node_index, nodes[node_index].nxt[c], id);
    }
  }

  void add(const string &str, int id) {
    add(str, 0, 0, id);
  }

  void add(const string &str) {
    add(str, nodes[0].exist);
  }

  void query(const string &str, const function<void(int)> &f, int str_index, int node_index) {
    for (auto &idx : nodes[node_index].accept) f(idx);
    if (str_index == str.size()) {
      return;
    } else {
      const int c = str[str_index] - margin;
      if (nodes[node_index].nxt[c] == -1) return;
      query(str, f, str_index + 1, nodes[node_index].nxt[c]);
    }
  }

  void query(const string &str, const function<void(int)> &f) {
    query(str, f, 0, 0);
  }

  int count() const {
    return (nodes[0].exist);
  }

  int size() const {
    return ((int)nodes.size());
  }
};
/*
trie_tree<26, 'a'> tt;
*/

void solve(int n, vector<string> s) {
  const string A = "a";
  vvs as(26);
  each(x, s)as[x.back() - 'a'].push_back(x);
  vector<trie_tree<26, 'a'>> tt(26);
  rep(i, 26)each(x, as[i])tt[i].add(A + x.substr(0, sz(x) - 1));
  int ans = 0;
  each(x, s) {
    int l = sz(x);
    vi cm(l + 1);
    rrep(j, l)cm[j] = cm[j + 1] | lshift(x[j] - 'a');
    rep(j, 26) {
      auto f = [&](int idx) {
        if((cm[sz(as[j][idx]) - 1] >> j) & 1){
          ans++;
        }
      };
      tt[j].query(A + x.substr(0, l - 1), f);
    }
  }
  COUT(ans - n);
}


#pragma region main
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cout << fixed << setprecision(15);

  int n;
  cin >> n;
  vector<string> s(n);
  for(int i = 0 ; i < n ; i++){
    cin >> s[i];
    rev(s[i]);
  }
  solve(n, move(s));
}
#pragma endregion main

Measured memory_bytes: 355520