// -*- coding:utf-8-unix -*-

#![allow(dead_code)]
#![allow(unused_imports)]

use std::cmp;
use std::cmp::Ordering;
use std::collections::*;
use std::convert::*;
use std::convert::{From, Into};
use std::fmt::Debug;
use std::fs::File;
use std::io::prelude::*;
use std::io::*;
use std::marker::Copy;
use std::mem::*;
use std::ops::{Add, Mul, Neg, Sub};
use std::str;
use std::vec;
const INF: i64 = 1223372036854775807;
const MEM_SIZE: usize = 202020;
const MOD: i64 = 1000000007;
// const MOD: i64 = 998244353;

use std::cmp::*;
use std::collections::*;
use std::io::stdin;
use std::io::stdout;
use std::io::Write;
#[allow(dead_code)]
fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

#[allow(dead_code)]
fn readi() -> (i64) {
    let mut str = String::new();
    let _ = stdin().read_line(&mut str).unwrap();
    let mut iter = str.split_whitespace();
    iter.next().unwrap().parse::<i64>().unwrap()
}

#[allow(dead_code)]
fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    read::<String>()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}
#[allow(dead_code)]
fn read_vec2<T: std::str::FromStr>(n: u32) -> Vec<Vec<T>> {
    (0..n).map(|_| read_vec()).collect()
}

#[allow(dead_code)]
fn readii() -> (i64, i64) {
    let mut str = String::new();
    let _ = stdin().read_line(&mut str).unwrap();
    let mut iter = str.split_whitespace();
    (
        iter.next().unwrap().parse::<i64>().unwrap(),
        iter.next().unwrap().parse::<i64>().unwrap(),
    )
}

fn readff() -> (f64, f64) {
    let mut str = String::new();
    let _ = stdin().read_line(&mut str).unwrap();
    let mut iter = str.split_whitespace();
    (
        iter.next().unwrap().parse::<f64>().unwrap(),
        iter.next().unwrap().parse::<f64>().unwrap(),
    )
}

#[allow(dead_code)]
fn readiii() -> (i64, i64, i64) {
    let mut str = String::new();
    let _ = stdin().read_line(&mut str).unwrap();
    let mut iter = str.split_whitespace();
    (
        iter.next().unwrap().parse::<i64>().unwrap(),
        iter.next().unwrap().parse::<i64>().unwrap(),
        iter.next().unwrap().parse::<i64>().unwrap(),
    )
}
#[allow(dead_code)]
fn readuu() -> (usize, usize) {
    let mut str = String::new();
    let _ = stdin().read_line(&mut str).unwrap();
    let mut iter = str.split_whitespace();
    (
        iter.next().unwrap().parse::<usize>().unwrap(),
        iter.next().unwrap().parse::<usize>().unwrap(),
    )
}

fn readcc() -> (char, char) {
    let mut str = String::new();
    let _ = stdin().read_line(&mut str).unwrap();
    let mut iter = str.split_whitespace();
    (
        iter.next().unwrap().parse::<char>().unwrap(),
        iter.next().unwrap().parse::<char>().unwrap(),
    )
}

#[allow(dead_code)]
fn readuuu() -> (usize, usize, usize) {
    let mut str = String::new();
    let _ = stdin().read_line(&mut str).unwrap();
    let mut iter = str.split_whitespace();
    (
        iter.next().unwrap().parse::<usize>().unwrap(),
        iter.next().unwrap().parse::<usize>().unwrap(),
        iter.next().unwrap().parse::<usize>().unwrap(),
    )
}

#[allow(dead_code)]
fn readuuuu() -> (usize, usize, usize, usize) {
    let mut str = String::new();
    let _ = stdin().read_line(&mut str).unwrap();
    let mut iter = str.split_whitespace();
    (
        iter.next().unwrap().parse::<usize>().unwrap(),
        iter.next().unwrap().parse::<usize>().unwrap(),
        iter.next().unwrap().parse::<usize>().unwrap(),
        iter.next().unwrap().parse::<usize>().unwrap(),
    )
}
/// Equivalent to std::lowerbound and std::upperbound in c++
pub trait BinarySearch<T> {
    fn lower_bound(&self, x: &T) -> usize;
    fn upper_bound(&self, x: &T) -> usize;
}
impl<T: Ord> BinarySearch<T> for [T] {
    fn lower_bound(&self, x: &T) -> usize {
        let mut low = 0;
        let mut high = self.len();
        while low != high {
            let mid = (low + high) / 2;
            match self[mid].cmp(x) {
                Ordering::Less => {
                    low = mid + 1;
                }
                Ordering::Equal | Ordering::Greater => {
                    high = mid;
                }
            }
        }
        low
    }
    fn upper_bound(&self, x: &T) -> usize {
        let mut low = 0;
        let mut high = self.len();
        while low != high {
            let mid = (low + high) / 2;
            match self[mid].cmp(x) {
                Ordering::Less | Ordering::Equal => {
                    low = mid + 1;
                }
                Ordering::Greater => {
                    high = mid;
                }
            }
        }
        low
    }
}
#[derive(PartialEq, Eq, Clone, Debug)]
enum Inf<T> {
    Val(T),
    Inf,
}
impl<T: Ord> Inf<T> {
    #[allow(dead_code)]
    fn val(self) -> Option<T> {
        match self {
            Inf::Val(v) => Some(v),
            _ => None,
        }
    }
}
impl<T: PartialOrd> PartialOrd for Inf<T> {
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
        match (self, other) {
            (&Inf::Inf, &Inf::Inf) => Some(Ordering::Equal),
            (&Inf::Inf, &Inf::Val(_)) => Some(Ordering::Greater),
            (&Inf::Val(_), &Inf::Inf) => Some(Ordering::Less),
            (&Inf::Val(ref a), &Inf::Val(ref b)) => a.partial_cmp(b),
        }
    }
}
impl<T: Ord> Ord for Inf<T> {
    fn cmp(&self, other: &Self) -> Ordering {
        match (self, other) {
            (&Inf::Inf, &Inf::Inf) => Ordering::Equal,
            (&Inf::Inf, &Inf::Val(_)) => Ordering::Greater,
            (&Inf::Val(_), &Inf::Inf) => Ordering::Less,
            (&Inf::Val(ref a), &Inf::Val(ref b)) => a.cmp(b),
        }
    }
}
#[allow(dead_code)]
/// Calculate length of Longest Increasing Subsequence. O(N log N)
pub fn lis(seq: &[i64]) -> usize {
    let mut dp: Vec<i64> = vec![INF as i64; seq.len() + 1];
    for x in seq.iter() {
        let mut xx = (*x);
        xx -= 1;
        let i = dp.upper_bound(&xx);
        dp[i] = xx;
    }
    dp.lower_bound(&INF)
}

fn solve() {
    let n: usize = read();
    let mut vec = vec![0; n];
    let mut ma = INF;
    for i in 0..n {
        let x: i64 = read();
        vec[i] = x;
    }
    vec.sort();
    vec.reverse();
    let mut cnt = 1 as usize;
    let mut res = 0;
    for i in 0..n - 1 {
        if vec[i] > vec[i + 1] + 1 {
            res = max(res, cnt);
            cnt = 1;
        } else {
            cnt += 1;
        }
        // res += 1;
    }
    res = max(res, cnt);

    println!("{:?}", res);
}

fn main() {
    solve()
}