use std::io::*;
const MOD: u64 = 1000000007;

fn mod_pow(mut x: u64, mut e: u64, m: u64) -> u64 {
    let mut res = 1;
    while e > 0 {
        if e & 1 == 1 {
            res = res * x % m;
        }
        x = x * x % m;
        e >>= 1;
    }
    res
}
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 a: Vec<usize> = (0..n)
        .map(|_| itr.next().unwrap().parse().unwrap())
        .collect();

    let mut large = 0;
    let mut small = 0;
    for i in 0..n {
        if a[i] > 50 {
            large += 1;
        } else if a[i] < 50 {
            small += 1;
        }
    }
    if large == 0 {
        println!("0");
    } else {
        println!("{}", mod_pow(2, large + small - 1, MOD));
    }
}