/*#include<fstream>
using namespace std;
ifstream in;
ofstream out;
/*                                                                                                               int unlan(int x){
	if(x%10==0)
		return 0;
	if(x%10==1)
		return 1;
	if(x%10==5)
		return 5;
	if(x%10==6)
		return 6;
	if(x%10==4 && x%4==1 || x%4==3)
		return 4;
	if(x%10==4 && x%4==0 || x%4==2)
		return 6;
	if(x%10==9 && x%4==0 || x%4==2)
		return 1;
	if(x%10==9 && x%4==3 || x%4==1)
		return 9;
	if(x%10==7 && x%4==1)
		return 7;
	if(x%10==7 && x%4==3)
		return 3;
	if(x%10==2 && x%4==2)
		return 4;
	if(x%10==2 && x%4==0)
		return 6;
	if(x%10==8 && x%4==2)
		return 4;
	if(x%10==8 && x%4==2)
		return 4;
	if(x%10==3 && x%4==1)
		return 3;
	if(x%10==3 && x%4==3)
		return 7;
}*/
/*int main(){
	int player_unu=0,n,s=0;
	in.open("ucif.in");
	out.open("ucif.out");
	in>>n;
	if(n==3)
		out<<2;
	/*for(int i=1;i<=n;i++)
	{
		s=s+unlan(i);
		out<<s<<endl;
	}*/
	//out<<s%10;
	/*in.close();
	out.close();
	return player_unu;
}*/
#include<stdio.h>
int main()
{
	freopen("ucif.in","r",stdin);
	freopen("ucif.out","w",stdout);
	int n,s=0,nr=1,j,i;
	scanf("%d",&n);
	for(i=1;i<=n;i++)
	{
		j=i;
		while(nr!=i)
		{
			j=j*i;
			j=j%10;
			nr++;
		}
		s=s+j;
		nr=1;
	}
	s=s%10;
	printf("%d",s);
	return 0;
}