#!/bin/python3

import sys


n = int(input().strip())
a = [int(a_temp) for a_temp in input().strip().split(' ')]
counts = [0]*101
for x in a:
    counts[x] += 1
counts2 = [0]*101
for i in range(len(counts)-1):
    counts2[i] = counts[i] + counts[i+1]
print(max(counts2))