Numbers - Range Count Python

Given N distinct integers, the program must print the number of ranges R present. A range is defined as two or more consecutive integers.

Input Format: 

The first line contains N. The second line contains N integer values separated by a space.

Output Format: 

The first line contains R.

Boundary Conditions:

2 <= N <= 100000

1 <= R <= 10000

Example Input/Output 1:

Input: 

5 2 1 4 9 3

Output:

 1

Explanation:

The only range which is present is 1 2 3 4.

9 is not a range (as a range needs two or more consecutive integers).

Example Input/Output 2:

Input:

7 1 3 11 -15 -20 9 5

Output:

0

Coding:

n=int(input())

a=[int(i)for i in input().split()]

a.sort()

c=1;b=[]

for i in range(len(a)-1):

    if a[i]+1==a[i+1]:

        c+=1

    else:

        b.append(c)

        c=1

b.append(c)

print(sum(i>1 for i in b))