#!/usr/bin/env python3 import sys def main(array): # Convert the input into numbers nums = [int(x) for x in array] # Take the last value as 'k' k = nums.pop() matches = 0 for i in range(len(array)-2): for j in range(i+1, len(array)-1): if (nums[i] + nums[j]) % k == 0: matches += 1 print(matches) if __name__ == '__main__': main(sys.argv[1:])