#include<fstream>
using namespace std;
ifstream fin("cifra.in");
ofstream fout("cifra.out");
int main()
{
	char n,t,i;
	int c,s,s1,s2,s3,s4,s5,s6,s7,s8,s9;
	fin>>t;
	s=0;
	for(i=1;i<=t;i++)
	{
		fin>>n;
		s=n/10*7;
		c=n%10;
		if(c==1)
		{
			s1=1;
			s=s+s1;
		}
		if(c==2)
		{
			if(n%4==2)s2=4;
			if(n%4==0)s2=6;
			s=s+s1+s2;
		}
		if(c==3)
		{
			if(n%4==1)s3=3;
			if(n%4==3)s3=7;
			s=s+s1+s2+s3;
		}
		if(c==4)
		{
			s4=6;
			s=s+s1+s2+s3+s4;
		}
		if(c==5)
		{
			s5=5;
			s=s+s1+s2+s3+s4+s5;
		}
		if(c==6)
		{
			s6=6;
			s=s+s1+s2+s3+s4+s5+s6;
		}
		if(c==7)
		{
			if(n%4==1)s7=7;
			if(n%4==3)s7=3;
			s=s+s1+s2+s3+s4+s5+s6+s7;
		}
		if(c==8)
		{
			if(n%4==0)s8=6;
			if(n%4==2)s8=4;
			s=s+s1+s2+s3+s4+s5+s6+s7+s8;
		}
		if(c==9)
		{
			s9=9;
			s=s+s1+s2+s3+s4+s5+s6+s7+s8+s9;
		}
	}
	fout<<s%10;
	fin.close();
	fout.close();
	return 0;
}