#include <cstdio>
int main()
{
	freopen ("ucif.in","r",stdin);
	freopen ("ucif.out","w",stdout);

	int s=0,n,i;
	scanf("%d",&n);
	for (i=1; i<=n; ++i)
	{
		switch (i%10)
		{
			case 0: s+=0; break;
			case 1: s+=1; break;
			case 2:	switch (i%4)
				{
					case 0: s+=6; break;
					case 1: s+=2; break;
					case 2: s+=4; break;
					case 3: s+=8; break;
				}
				break;
			case 3: switch (i%4)
				{
					case 0: s+=1; break;
					case 1: s+=3; break;
					case 2: s+=9; break;
					case 3: s+=7; break;
				}
				break;
			case 4: switch (i%2)
				{
					case 0: s+=6; break;
					case 1: s+=4; break;
				}
                                break;
			case 5: s+=5; break;
			case 6: s+=6; break;
			case 7: switch (i%4)
				{
					case 0: s+=1; break;
					case 1: s+=7; break;
					case 2: s+=9; break;
					case 3: s+=3; break;
				}
				break;
			case 8: switch (i%4)
				{
					case 0: s+=6; break;
					case 1: s+=8; break;
					case 2: s+=4; break;
					case 3: s+=2; break;
				}
				break;
			case 9: switch (i%2)
				{
					case 0: s+=1; break;
					case 1: s+=9; break;
				}
				break;
		}
		if (s>9)
			s%=10;
        }
	printf("%d",s);
        return 0;
}