#include<bits/stdc++.h>
using namespace std;
int main()
{
    int a[500000];
    int n, m=1;
    cin>>n;
    int q, r=0;
    a[0]=1;
    int i=2;
    for (i; i<=n; i++)
        for(int j=0; j<m; j++)
        {
            q = r;
            r = (a[j]*i + r)/10;
            a[j] = (a[j]*i + q)%10;
        }
    while(r>0)
    {
        a[m] = r % 10;
        m++;
        r = r/10;
    }
    for ( int j=m-1; j>=0; j--)
        cout<<a[j];
}