#include<bits/stdc++.h>
using namespace std;
int cf(int x,int y)
{
	int a[100001]={},b[100001]={},jw[100001]={},c[100001]={},i=1,j=1,op=0;
	while(x>=1){
		i++;
		a[i]=x%10;
		x/=10;
	}
	while(y>=1){
		j++;
		b[j]=y%10;
		y/=10;
	}
	int k=max(i,j);
	for(int m=1;m<=k;m++){
		c[m]=((a[m]*b[m])%10+jw[m-1])%10;
		jw[m]=(a[m]*b[m])/10;
	}
	for(int h=1;h<=k;j++){
		op=op+c[h]*10;
	}
	return op;
}
int jc(int n)
{
	if(n==1)return 1;
	return cf(n,jc(n-1));
}
int main()
{
	int n,i,s=0;
	cin>>n;
	for(i=1;i<=n;i++){
		s=s+jc(i);
	}
	cout<<s;
	return 0;
}