use proconio::input;
use std::collections::HashSet;

fn main() {
	input! {
		n: usize,
		s: [String; n],
	}

    let mut hash_set = HashSet::new();

    for i in 0..n {
        for j in 0..n {
            if i == j {
                continue;
            }

            hash_set.insert(format!("{}{}", s[i], s[j]));
        }
    }

    println!("{}", hash_set.len());
}