use proconio::input;

fn main() {
    input! {
        n: usize,
        mut a: i64, mut b: i64,
        p: [i64; n],
    }

    for i in 0..n {
        if p[i] == 1 {
            a -= 1;
        }
        else if p[i] == 2 {
            b -= 1;
        }
        else {
            a -= 1; b -= 1;
        }

        if a < 0 || b < 0 {
            println!("{}", i+1);
            return;
        }
    }
    println!("-1");
}