Divisible sum pair - Program to check the sum pair matching the given number

Paired_Sum.py

# This is a test case, please check my git rrepo for the code that goes on HackerRank
def pair(a,num):
    b = a
    count = 0
    for i in range(len(a)-1):
        for j in range(i+1,len(b)):
            if (a[i] + b[j]) % num == 0:
                count += 1
    return count
    
a = [1,2,3,4,5,6]
num = 5
print(pair(a,num))