// ---------- begin chmin, chmax ----------
pub trait ChangeMinMax {
    fn chmin(&mut self, x: Self) -> bool;
    fn chmax(&mut self, x: Self) -> bool;
}

impl<T: PartialOrd> ChangeMinMax for T {
    fn chmin(&mut self, x: Self) -> bool {
        *self > x && {
            *self = x;
            true
        }
    }
    fn chmax(&mut self, x: Self) -> bool {
        *self < x && {
            *self = x;
            true
        }
    }
}
// ---------- end chmin, chmax ----------

fn read() -> (usize, Vec<i64>, Vec<i64>) {
    let mut s = String::new();
    use std::io::Read;
    std::io::stdin().read_to_string(&mut s).unwrap();
    let mut it = s.trim().split_whitespace();
    let mut next = || it.next().unwrap().parse::<i64>().unwrap();
    let k = next() as usize;
    let n = next() as usize;
    let a = (0..k).map(|_| next()).collect::<Vec<_>>();
    let b = (0..k).map(|_| next()).collect::<Vec<_>>();
    (n, a, b)
}

const INF: i64 = 1_000_000_000_000_000_000 + 1;

fn solve(n: usize, a: &[i64], b: &[i64]) -> i64 {
    if n < a.len() {
        return a[n];
    }
    let k = a.len();
    let mut ok = -INF;
    let mut ng = INF;
    while ng - ok > 1 {
        let mid = (ok + ng) / 2;
        let a = a.iter().map(|a| *a >= mid).collect::<Vec<_>>();
        let b = b.iter().map(|a| *a >= mid).collect::<Vec<_>>();
        let mut c = vec![false; 2 * k];
        c[..k].copy_from_slice(&a);
        for i in 0..k {
            c[i + k] = c[i..].iter().zip(b.iter()).any(|p| *p.0 && *p.1);
        }
        if n < 2 * k {
            if c[n] {
                ok = mid;
            } else {
                ng = mid;
            }
            continue;
        }
        if c[k..].iter().all(|p| !*p) {
            ng = mid;
            continue;
        }
        let len = c.iter().rposition(|c| *c).unwrap() + 1 - k;
        let mut dp = vec![n + 1; len];
        for (i, c) in c[k..].iter().enumerate() {
            if *c {
                dp[i] = k + i;
            }
        }
        let mut used = vec![false; len];
        for _ in 1..len {
            let x = (0..len).filter(|p| !used[*p]).min_by_key(|p| dp[*p]).unwrap();
            used[x] = true;
            let v = dp[x];
            for (i, c) in b.iter().enumerate() {
                if *c {
                    dp[(x + k - i) % len].chmin(v + k - i);
                }
            }
        }
        if dp[(n - k) % len] <= n {
            ok = mid;
        } else {
            ng = mid;
        }
    }
    ok
}

fn run() {
    let (n, a, b) = read();
    let ans = solve(n, &a, &b);
    println!("{}", ans);
}

fn main() {
    run();
}