fn main() {
    #![allow(unused_imports, unused_macros)]
    prepare_io!(_in_buf, scanner, _out);
    macro_rules ! print { ($ ($ arg : tt) *) => (:: std :: write ! (_out , $ ($ arg) *) . expect ("io error")) }
    macro_rules ! println { ($ ($ arg : tt) *) => (:: std :: writeln ! (_out , $ ($ arg) *) . expect ("io error")) }
    scan!(scanner, n, s: [{CharsWithBase('a')};n]);
    let mut c = vec![vec![0usize; 26]; 26];
    for s in s {
        if s.windows(2).all(|w| w[0] <= w[1]) {
            if s.first() == s.last() {
                let x = s.first().cloned().unwrap();
                c[x][x] += s.len();
            } else {
                let x = s.first().cloned().unwrap();
                let y = s.last().cloned().unwrap();
                c[x][y].chmax(s.len());
            }
        }
    }
    let mut dp = vec![0usize; 26];
    for i in 0..26 {
        if i > 0 {
            chmax!(dp[i], dp[i - 1]);
        }
        dp[i] += c[i][i];
        for j in i + 1..26 {
            chmax!(dp[j], dp[i] + c[i][j]);
        }
    }
    println!("{}", dp[25]);
}
#[macro_export]
macro_rules! prepare_io {
    ($ in_buf : ident , $ scanner : ident , $ out : ident) => {
        use std::io::{stdout, BufWriter, Write as _};
        let $in_buf = read_stdin_all_unchecked();
        let mut $scanner = Scanner::new(&$in_buf);
        let $out = stdout();
        let mut $out = BufWriter::new($out.lock());
    };
}
pub fn echo<T: std::fmt::Display>(
    mut writer: impl std::io::Write,
    iter: impl IntoIterator<Item = T>,
    sep: impl std::fmt::Display,
) -> std::io::Result<()> {
    let mut iter = iter.into_iter();
    if let Some(item) = iter.next() {
        write!(writer, "{}", item)?;
    }
    for item in iter {
        write!(writer, "{}{}", sep, item)?;
    }
    writeln!(writer)
}
pub fn read_stdin_all_unchecked() -> String {
    use std::io::Read as _;
    let mut buf = Vec::new();
    std::io::stdin().read_to_end(&mut buf).expect("io error");
    unsafe { String::from_utf8_unchecked(buf) }
}
pub fn read_stdin_line() -> String {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).expect("io error");
    s
}
pub use scanner_impls::{IterScan, MarkedIterScan, Scanner};
mod scanner_impls {
    pub trait IterScan: Sized {
        type Output;
        fn scan<'a, I: Iterator<Item = &'a str>>(iter: &mut I) -> Option<Self::Output>;
    }
    pub trait MarkedIterScan: Sized {
        type Output;
        fn mscan<'a, I: Iterator<Item = &'a str>>(self, iter: &mut I) -> Option<Self::Output>;
    }
    #[derive(Clone, Debug)]
    pub struct Scanner<'a> {
        iter: std::str::SplitAsciiWhitespace<'a>,
    }
    impl<'a> Scanner<'a> {
        #[inline]
        pub fn new(s: &'a str) -> Self {
            let iter = s.split_ascii_whitespace();
            Self { iter }
        }
        #[inline]
        pub fn scan<T>(&mut self) -> <T as IterScan>::Output
        where
            T: IterScan,
        {
            <T as IterScan>::scan(&mut self.iter).expect("scan error")
        }
        #[inline]
        pub fn mscan<T>(&mut self, marker: T) -> <T as MarkedIterScan>::Output
        where
            T: MarkedIterScan,
        {
            marker.mscan(&mut self.iter).expect("scan error")
        }
        #[inline]
        pub fn scan_vec<T>(&mut self, size: usize) -> Vec<<T as IterScan>::Output>
        where
            T: IterScan,
        {
            (0..size)
                .map(|_| <T as IterScan>::scan(&mut self.iter).expect("scan error"))
                .collect()
        }
        #[inline]
        pub fn iter<'b, T>(&'b mut self) -> ScannerIter<'a, 'b, T>
        where
            T: IterScan,
        {
            ScannerIter {
                inner: self,
                _marker: std::marker::PhantomData,
            }
        }
    }
    macro_rules ! iter_scan_impls { ($ ($ t : ty) *) => { $ (impl IterScan for $ t { type Output = Self ; # [inline] fn scan <'a , I : Iterator < Item = &'a str >> (iter : & mut I) -> Option < Self > { iter . next () ?. parse ::<$ t > () . ok () } }) * } ; }
    iter_scan_impls ! (char u8 u16 u32 u64 usize i8 i16 i32 i64 isize f32 f64 u128 i128 String);
    macro_rules ! iter_scan_tuple_impl { ($ ($ T : ident) *) => { impl <$ ($ T : IterScan) ,*> IterScan for ($ ($ T ,) *) { type Output = ($ (<$ T as IterScan >:: Output ,) *) ; # [inline] fn scan <'a , It : Iterator < Item = &'a str >> (_iter : & mut It) -> Option < Self :: Output > { Some (($ (<$ T as IterScan >:: scan (_iter) ?,) *)) } } } ; }
    iter_scan_tuple_impl!();
    iter_scan_tuple_impl!(A);
    iter_scan_tuple_impl ! (A B);
    iter_scan_tuple_impl ! (A B C);
    iter_scan_tuple_impl ! (A B C D);
    iter_scan_tuple_impl ! (A B C D E);
    iter_scan_tuple_impl ! (A B C D E F);
    iter_scan_tuple_impl ! (A B C D E F G);
    iter_scan_tuple_impl ! (A B C D E F G H);
    iter_scan_tuple_impl ! (A B C D E F G H I);
    iter_scan_tuple_impl ! (A B C D E F G H I J);
    iter_scan_tuple_impl ! (A B C D E F G H I J K);
    pub struct ScannerIter<'a, 'b, T> {
        inner: &'b mut Scanner<'a>,
        _marker: std::marker::PhantomData<fn() -> T>,
    }
    impl<'a, 'b, T> Iterator for ScannerIter<'a, 'b, T>
    where
        T: IterScan,
    {
        type Item = <T as IterScan>::Output;
        #[inline]
        fn next(&mut self) -> Option<Self::Item> {
            <T as IterScan>::scan(&mut self.inner.iter)
        }
    }
}
pub use marker_impls::{CharWithBase, Chars, CharsWithBase, Collect, SizedCollect, Usize1};
mod marker_impls {
    use super::*;
    use std::{
        iter::{repeat_with, FromIterator},
        marker::PhantomData,
    };
    #[derive(Debug, Copy, Clone)]
    pub struct Usize1;
    impl IterScan for Usize1 {
        type Output = usize;
        #[inline]
        fn scan<'a, I: Iterator<Item = &'a str>>(iter: &mut I) -> Option<Self::Output> {
            <usize as IterScan>::scan(iter)?.checked_sub(1)
        }
    }
    #[derive(Debug, Copy, Clone)]
    pub struct CharWithBase(pub char);
    impl MarkedIterScan for CharWithBase {
        type Output = usize;
        #[inline]
        fn mscan<'a, I: Iterator<Item = &'a str>>(self, iter: &mut I) -> Option<Self::Output> {
            Some((<char as IterScan>::scan(iter)? as u8 - self.0 as u8) as usize)
        }
    }
    #[derive(Debug, Copy, Clone)]
    pub struct Chars;
    impl IterScan for Chars {
        type Output = Vec<char>;
        #[inline]
        fn scan<'a, I: Iterator<Item = &'a str>>(iter: &mut I) -> Option<Self::Output> {
            Some(iter.next()?.chars().collect())
        }
    }
    #[derive(Debug, Copy, Clone)]
    pub struct CharsWithBase(pub char);
    impl MarkedIterScan for CharsWithBase {
        type Output = Vec<usize>;
        #[inline]
        fn mscan<'a, I: Iterator<Item = &'a str>>(self, iter: &mut I) -> Option<Self::Output> {
            Some(
                iter.next()?
                    .chars()
                    .map(|c| (c as u8 - self.0 as u8) as usize)
                    .collect(),
            )
        }
    }
    #[derive(Debug, Copy, Clone)]
    pub struct Collect<T, B = Vec<<T as IterScan>::Output>>
    where
        T: IterScan,
        B: FromIterator<<T as IterScan>::Output>,
    {
        size: usize,
        _marker: PhantomData<fn() -> (T, B)>,
    }
    impl<T, B> Collect<T, B>
    where
        T: IterScan,
        B: FromIterator<<T as IterScan>::Output>,
    {
        pub fn new(size: usize) -> Self {
            Self {
                size,
                _marker: PhantomData,
            }
        }
    }
    impl<T, B> MarkedIterScan for Collect<T, B>
    where
        T: IterScan,
        B: FromIterator<<T as IterScan>::Output>,
    {
        type Output = B;
        #[inline]
        fn mscan<'a, I: Iterator<Item = &'a str>>(self, iter: &mut I) -> Option<Self::Output> {
            repeat_with(|| <T as IterScan>::scan(iter))
                .take(self.size)
                .collect()
        }
    }
    #[derive(Debug, Copy, Clone)]
    pub struct SizedCollect<T, B = Vec<<T as IterScan>::Output>>
    where
        T: IterScan,
        B: FromIterator<<T as IterScan>::Output>,
    {
        _marker: PhantomData<fn() -> (T, B)>,
    }
    impl<T, B> IterScan for SizedCollect<T, B>
    where
        T: IterScan,
        B: FromIterator<<T as IterScan>::Output>,
    {
        type Output = B;
        #[inline]
        fn scan<'a, I: Iterator<Item = &'a str>>(iter: &mut I) -> Option<Self::Output> {
            let size = usize::scan(iter)?;
            repeat_with(|| <T as IterScan>::scan(iter))
                .take(size)
                .collect()
        }
    }
}
#[macro_export]
macro_rules ! scan_value { ($ scanner : expr , ($ ($ t : tt) ,*)) => { ($ ($ crate :: scan_value ! ($ scanner , $ t)) ,*) } ; ($ scanner : expr , [$ t : tt ; $ len : expr]) => { (0 ..$ len) . map (| _ | $ crate :: scan_value ! ($ scanner , $ t)) . collect ::< Vec < _ >> () } ; ($ scanner : expr , [$ t : ty ; $ len : expr]) => { $ scanner . scan_vec ::<$ t > ($ len) } ; ($ scanner : expr , [$ t : ty]) => { $ scanner . iter ::<$ t > () } ; ($ scanner : expr , { $ e : expr }) => { $ scanner . mscan ($ e) } ; ($ scanner : expr , $ t : ty) => { $ scanner . scan ::<$ t > () } ; }
#[macro_export]
macro_rules ! scan { ($ scanner : expr) => { } ; ($ scanner : expr ,) => { } ; ($ scanner : expr , mut $ var : tt : $ t : tt) => { let mut $ var = $ crate :: scan_value ! ($ scanner , $ t) ; } ; ($ scanner : expr , $ var : tt : $ t : tt) => { let $ var = $ crate :: scan_value ! ($ scanner , $ t) ; } ; ($ scanner : expr , mut $ var : tt : $ t : tt , $ ($ rest : tt) *) => { let mut $ var = $ crate :: scan_value ! ($ scanner , $ t) ; scan ! ($ scanner , $ ($ rest) *) } ; ($ scanner : expr , $ var : tt : $ t : tt , $ ($ rest : tt) *) => { let $ var = $ crate :: scan_value ! ($ scanner , $ t) ; scan ! ($ scanner , $ ($ rest) *) } ; ($ scanner : expr , mut $ var : tt) => { let mut $ var = $ crate :: scan_value ! ($ scanner , usize) ; } ; ($ scanner : expr , $ var : tt) => { let $ var = $ crate :: scan_value ! ($ scanner , usize) ; } ; ($ scanner : expr , mut $ var : tt , $ ($ rest : tt) *) => { let mut $ var = $ crate :: scan_value ! ($ scanner , usize) ; scan ! ($ scanner , $ ($ rest) *) } ; ($ scanner : expr , $ var : tt , $ ($ rest : tt) *) => { let $ var = $ crate :: scan_value ! ($ scanner , usize) ; scan ! ($ scanner , $ ($ rest) *) } ; }
pub trait PartialOrdExt: Sized {
    fn chmin(&mut self, other: Self);
    fn chmax(&mut self, other: Self);
    fn minmax(self, other: Self) -> (Self, Self);
}
impl<T> PartialOrdExt for T
where
    T: PartialOrd,
{
    #[inline]
    fn chmin(&mut self, other: Self) {
        if *self > other {
            *self = other;
        }
    }
    #[inline]
    fn chmax(&mut self, other: Self) {
        if *self < other {
            *self = other;
        }
    }
    #[inline]
    fn minmax(self, other: Self) -> (Self, Self) {
        if self < other {
            (self, other)
        } else {
            (other, self)
        }
    }
}
#[macro_export]
macro_rules ! min { ($ l : expr) => { $ l } ; ($ l : expr ,) => { $ crate :: min ! ($ l) } ; ($ l : expr , $ r : expr) => { ($ l) . min ($ r) } ; ($ l : expr , $ r : expr ,) => { $ crate :: min ! ($ l , $ r) } ; ($ l : expr , $ r : expr , $ ($ t : tt) *) => { $ crate :: min ! ($ crate :: min ! ($ l , $ r) , $ ($ t) *) } ; }
#[macro_export]
macro_rules ! chmin { ($ l : expr) => { } ; ($ l : expr ,) => { } ; ($ l : expr , $ r : expr) => { { let r = $ r ; if $ l > r { $ l = r ; } } } ; ($ l : expr , $ r : expr ,) => { $ crate :: chmin ! ($ l , $ r) } ; ($ l : expr , $ r : expr , $ ($ t : tt) *) => { $ crate :: chmin ! ($ l , $ r) ; $ crate :: chmin ! ($ l , $ ($ t) *) } ; }
#[macro_export]
macro_rules ! max { ($ l : expr) => { $ l } ; ($ l : expr ,) => { $ crate :: max ! ($ l) } ; ($ l : expr , $ r : expr) => { ($ l) . max ($ r) } ; ($ l : expr , $ r : expr ,) => { $ crate :: max ! ($ l , $ r) } ; ($ l : expr , $ r : expr , $ ($ t : tt) *) => { $ crate :: max ! ($ crate :: max ! ($ l , $ r) , $ ($ t) *) } ; }
#[macro_export]
macro_rules ! chmax { ($ l : expr) => { } ; ($ l : expr ,) => { } ; ($ l : expr , $ r : expr) => { { let r = $ r ; if $ l < r { $ l = r ; } } } ; ($ l : expr , $ r : expr ,) => { $ crate :: chmax ! ($ l , $ r) } ; ($ l : expr , $ r : expr , $ ($ t : tt) *) => { $ crate :: chmax ! ($ l , $ r) ; $ crate :: chmax ! ($ l , $ ($ t) *) } ; }
#[macro_export]
macro_rules ! minmax { ($ ($ t : tt) *) => { ($ crate :: min ! ($ ($ t) *) , $ crate :: max ! ($ ($ t) *)) } ; }