#include<iostream>
#include<stdio.h>
#include<cmath>
#include<algorithm>
#include<cstdio>
#include<cstring>
#include<string>
using namespace std;
int main(){
int m=10000000,n;
cin>>n;
int sum[m]={0};
int ans[m]={0};
int t=0;
ans[0]=1;
for(int i=1;i<=n;i++){
	t=0;
	for(int j=0;j<i;j++){
		ans[j]=ans[j]*i+t;
		t=ans[j]/10;
		ans[j]%=10;
	}
	t=0;
	for(int j=0;j<i;j++){
		sum[j]=ans[j]+sum[j]+t;
		t=sum[j]/10;
		sum[j]%=10;
	}
}
int Y=m-1;
while(sum[Y]==0)Y--;
for(int i=Y;i>=0;i--)
{
	cout<<sum[i];
 } 
	return 0;
}