use proconio::input;
use std::collections::HashMap;

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

    // x <= y
    // if x == 1 かつ y == 1 => 2
    // if x == 1 かつ y == 2 => 3
    // if x == 1 かつ 3 <= y => 2
    // else => 1

    let mut map = HashMap::new();
    for &x in &a {
        *map.entry(if x != 1 && x != 2 { 3 } else { x }).or_insert(0) += 1;
    }

    let mut res = 0_usize;
    let one = map.get(&1);
    let two = map.get(&2);
    let other = map.get(&3);

    if let Some(&onec) = one {
        res += 2 * onec * (onec - 1) / 2;
        if let Some(&tc) = two {
            res += 3 * onec * tc;
        }

        if let Some(&oc) = other {
            res += 2 * onec * oc;
        }
    }

    match (two, other) {
        (Some(tc), Some(oc)) => {
            res += tc * (tc - 1) / 2;
            res += oc * (oc - 1) / 2;
            res += oc * tc;
        }
        (None, Some(oc)) => {
            res += oc * (oc - 1) / 2;
        }
        (Some(tc), None) => {
            res += tc * (tc - 1) / 2;
        }
        (None, None) => {}
    }

    println!("{res}");
}