use proconio::input;

const MOD: usize = 1_000_000_007;

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

    if a.contains(&0) {
        println!("-1");
        return;
    }

    let mut result = 1;

    for i in 0..n {
        let x = a[i];

        if x == 1 {
            continue;
        }

        if let Some(fac_x) = factorial(x) {
            result *= x.pow(fac_x as u32);

            if result > MOD {
                println!("{}", MOD);
                return;
            }
        } else {
            println!("{}", MOD);
            return;
        }
    }

    if result == 0 {
        println!("-1");
        return;
    }

    println!("{}", MOD % result);
}

fn factorial(n: usize) -> Option<usize> {
    if n == 0 {
        return Some(1);
    }

    let mut result = 1;

    for i in (1..=n).rev() {
        result *= i;

        if result > MOD {
            return None;
        }
    }

    Some(result)
}