# https://projecteuler.net/problem=20
#
# n! means n × (n − 1) × ... × 3 × 2 × 1
# 
# For example, 10! = 10 × 9 × ... × 3 × 2 × 1 = 3628800,
# and the sum of the digits in the number 10! is 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27.
# 
# Find the sum of the digits in the number 100!

def preCalcFactSum(limit):
	ary = [1]
	f = 1
	for i in range(1, limit+1):
		f *= i
		n = f
		s = 0
		while n:
			s, n = s + n % 10, n // 10
		ary.append(s)
	return ary

if __name__ == '__main__':
	table = preCalcFactSum(100)
	print(table[-1])