//https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8 より
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };
    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}

//

fn lcp(a: &[char], b: &[char]) -> usize {
    let mut ans = 0;
    for (a, b) in a.iter().zip(b.iter()) {
        if *a == *b {
            ans += 1;
        } else {
            break;
        }
    }
    ans
}

fn calc(s: &[Vec<char>]) -> usize {
    let n = s.len();
    if n == 1 {
        return s[0].len();
    }
    let m = n / 2;
    let mut ans = calc(&s[..m]) + calc(&s[m..]);
    let v = lcp(&s[m], &s[m - 1]);
    let mut a = vec![];
    let mut u = v;
    for t in s[m..].iter() {
        u = lcp(&s[m][..u], t);
        a.push(u);
    }
    let mut b = vec![];
    let mut u = v;
    for t in s[..m].iter().rev() {
        u = lcp(&s[m][..u], t);
        b.push(u);
    }
    while a.len() > 0 && b.len() > 0 {
        let x = a.len();
        let y = b.len();
        let p = *a.last().unwrap();
        let q = *b.last().unwrap();
        if p <= q {
            let sum_len = (x + y) * (x + y + 1) / 2 - x * (x + 1) / 2;
            ans += p * sum_len;
            a.pop();
        } else {
            let sum_len = (x + y) * (x + y + 1) / 2 - y * (y + 1) / 2;
            ans += q * sum_len;
            b.pop();
        }
    }
    ans
}

fn run() {
    input! {
        n: usize,
        s: [chars; n],
    }
    let ans = calc(&s);
    println!("{}", ans);
}

fn main() {
    run();
}