from datetime import datetime
start_time = datetime.now()
def sumsquarediff(n):
  a=0
  b=0
  a= (n*(n+1))/2
  a=a*a
  b=(n*(n+1)*(2*n+1))/6
  c=a-b
  return c
print(sumsquarediff(100))

# program over
end_time = datetime.now()
print('Duration: {}'.format(end_time - start_time))
