#include<bits/stdc++.h>
using namespace std;
int a[1005]={1};
int main()
{
    int n ;
    cin >> n;
    int k = 1; 

    
    for(int i = n;i > 0;i--)
    {
        
        for (int j =0;j<k;j++)
        {
            a[j] = a[j] * i;
        }
        
        //进位
        for( int j = 0 ;j < k + 2 ; j++)
        {
            if ( a[j]  >= 10)
            {
                a[j + 1] = a[j+1] + a[j] /10;
                a[j] = a[j] % 10; 
            }
        }

        if (a[k+1]!=0) k+=2;
        else if(a[k]!=0) k+=1;

    }
    
    for(int i = k-1;i>=0;i--) cout << a[i];

    return 0;
}
/**************************************************************
	Problem: 1285
	User: mariooo
	Language: C++
	Result: Accepted
	Time:15 ms
	Memory:2076 kb
****************************************************************/