#include <iostream>
#include <string>
using namespace std;

int main()
{
	string a;
	int *q,d,i;
	cin>>a;
	d=a.length();
	q=new int[d];
	memset(q,0,4*d);
	do
	{
		for (i=0;i<d;i++)
		{
			q[i]+=a[i]-48;
			q[i]%=10;
		}
	}
	while (cin>>a);
	for (i=0;i<d;i++)
		cout<<q[i];
	cout<<endl;
	return 0;
}