def pickingNumbers(a):
    a = sorted(a)
    
    ans = 2
    temp = 0
    benchmark = a[0]
    
    for num in a:
        if abs(num-benchmark) <= 1:
            temp += 1
        else:
            ans = temp if temp > ans else ans
            temp = 1
            benchmark = num
            
    return ans if temp < ans else temp