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 mut a: u64 = i as u64 - pos + 1;
                let mut b: u64 = 1;
                while a > 1 {
                    ans += cnt * a * b;
                    a -= 1;
                    b += 1;
                }
            }
            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;
        }
        if m > 0 {
            // 今よりマッチ数が小さくなるまでpop
            let mut need: bool = true;
            while let Some((cnt, pos)) = stack.pop() {
                if cnt == m {
                    need = false;
                    stack.push((cnt, pos));
                    break;
                } else if cnt < m {
                    stack.push((cnt, pos));
                    break;
                }
                let mut a: u64 = i as u64 - pos + 1;
                let mut b: u64 = 1;
                while a > 1 {
                    ans += (cnt - m) * a * b;
                    a -= 1;
                    b += 1;
                }
            }
            if need {
                stack.push((m, i as u64));
            }
        }
    }
    println!("{}", ans);
}