using System;
using System.Numerics;
public class Solution {
static public void Main(String[] args) {
BigInteger sum;
int n = 100;
BigInteger fact = 1;
for(int j=2;j<=n;j++){
fact*=j;
}
sum=0;
while(fact>0){
sum+=fact%10;
fact= (fact-fact%10)/10;
Console.WriteLine(sum);