#include <iostream>
#include <string>
using namespace std;
#define NUM 100
void
multi(string *ps, int num)
{
string s("");
int c = 0;
for (string::size_type i = ps->size(); i > 0; i--)
{
int n = (ps->at(i-1)-'0') * num + c;
c = n/10;
s += '0' + n%10;
}
if (c != 0)
{
while (c != 0)
{
s += '0' + (c%10);
c /= 10;
}
}
*ps = "";
for (string::size_type i = 0; i < s.size(); i++)
{
*ps += s[s.size()-i-1];
}
}
int
main(int argc, char **argv)
{
string s = "1";
int ans = 0;
for (int i = 2; i <= NUM ; i++)
{
multi(&s, i);
}
for (string::iterator it = s.begin(), end = s.end(); it != end; it++)
{
ans += *it - '0';
}
cout << ans << endl;
return 0;
}