use std::collections::VecDeque;

use proconio::{fastout, input};

#[fastout]
fn main() {
    input! {
        n: usize,
        s: usize,
        mut a: [usize; n],
    }
    a.sort_unstable();
    a.reverse();

    let mut x = s;
    let mut v = VecDeque::new();
    while x > 0 {
        let idx = a.partition_point(|&p| p >= x);
        if idx == n {
            break;
        }

        x -= a[idx] + 1;
        v.push_back((idx, a[idx] + 1));
    }

    for i in 1..v.len() {
        if v[i].0 <= v[i - 1].0 {
            v[i] = (v[i - 1].0 + 1, v[i].1);
        }
    }

    if v.is_empty() {
        println!("{}", a.iter().sum::<usize>());
        return;
    }

    let mut ans = 0;
    let mut cnt = 0;
    while cnt < n {
        let mut nv = VecDeque::new();
        for _ in 0..v.len() {
            let (idx, x) = v.pop_front().unwrap();

            if idx >= n {
                continue;
            }

            if a[idx] == 0 {
                continue;
            }

            if x > a[idx] {
                cnt += 1;
                a[idx] = 0;
                if idx + 1 < n {
                    nv.push_back((idx + 1, x));
                } else if idx > 0 {
                    nv.push_back((idx - 1, x));
                } else {
                    continue;
                }
            } else {
                a[idx] -= 1;

                if a[idx] == 0 {
                    cnt += 1;
                    if idx > 0 {
                        nv.push_back((idx - 1, x));
                    }
                }
            }
        }

        v = nv;
        ans += 1;
    }

    println!("{}", ans);
}