use std::io::Read;

fn main() {
  let mut s: String = String::new();
  std::io::stdin().read_to_string(&mut s).ok();
  let mut itr = s.trim().split_whitespace();
  let n: usize = itr.next().unwrap().parse().unwrap();
  let s: Vec<Vec<char>> = (0..n)
    .map(|_| itr.next().unwrap().chars().collect())
    .collect();

  let mut ans: u64 = 0;
  let mut stack: Vec<(u64, u64)> = Vec::new();
  for i in 0..n {
    ans += s[i].len() as u64;
    if i == n - 1 {
      while let Some((cnt, pos)) = stack.pop() {
        let l = i as u64 - pos + 1;
        if let Some((c, p)) = stack.pop() {
          ans += (cnt - c) * (l * (l + 1) * (l + 2) / 6 - l);
          stack.push((c, p));
        } else {
          ans += cnt * (l * (l + 1) * (l + 2) / 6 - l);
        }
      }
      break;
    }
    let mut m: u64 = 0;
    let k = std::cmp::min(s[i].len(), s[i + 1].len());
    for j in 0..k {
      if s[i][j] != s[i + 1][j] {
        break;
      }
      m += 1;
    }
    // 今よりマッチ数が小さくなるまでpop
    let mut next: u64 = i as u64;
    while let Some((cnt, pos)) = stack.pop() {
      if cnt == m {
        next = pos;
        break;
      } else if cnt < m {
        stack.push((cnt, pos));
        break;
      }

      let l = i as u64 - pos + 1;
      if let Some((c, p)) = stack.pop() {
        ans += (cnt - std::cmp::max(m, c)) * (l * (l + 1) * (l + 2) / 6 - l);
        // 自分と同じ一番前を取得
        stack.push((c, p));
      } else {
        ans += (cnt - m) * (l * (l + 1) * (l + 2) / 6 - l);
      }
      next = pos;
    }
    stack.push((m, next));
  }
  println!("{}", ans);
}