fn main() {
    const M: usize = 1_000_000_007;

    let n: usize = {
        let mut buf = String::new();
        std::io::stdin().read_line(&mut buf).unwrap();
        buf.trim_end().parse().unwrap()
    };

    let mut a: Vec<usize> = {
        let mut buf = String::new();
        std::io::stdin().read_line(&mut buf).unwrap();
        let iter = buf.split_whitespace();
        iter.map(|x| x.parse().unwrap()).collect()
    };

    for i in 0..(n - 1) {
        for j in 0..(n - 1 - i) {
            a[j] = (a[j] + a[j + 1]) % M;
        }
    }

    println!("{}", a[0]);
}