#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <string>
using namespace std;
int maps[20] = {
0,1,5,2,8,3,9,2,8,7,
7,8,4,7,3,8,4,1,5,4};
int main()
{
string str;
while( cin >> str) {
int len = str.length();
if (len == 1 && str[0] == 0 )
break;
int value = str[len-1]-0;
if ( len > 1 ) {
value += (str[len-2]-0)*10;
}
cout << (maps[value%20] + (value/20)*4)%10 << endl;
}
return 0;
}