var a:array[1..20] of byte;
    s:string[101];
    p:string[2];
    f:text;
    n,h,x,m:integer;

BEGIN
a[1]:=1;a[2]:=5;a[3]:=2;a[4]:=8;a[5]:=3;
a[6]:=9;a[7]:=2;a[8]:=8;a[9]:=7;a[10]:=7;
a[11]:=8;a[12]:=4;a[13]:=7;a[14]:=3;a[15]:=8;
a[16]:=4;a[17]:=1;a[18]:=5;a[19]:=4;a[20]:=4;
assign(f,'cifra.in');reset(f);
readln(f,s);
close(f);
p:='';
p:=p+s[length(s)-1]+s[length(s)];
val(p,n,h);
x:=a[n mod 20];
m:=(n mod 100)div 20;
x:=x+4*(m-1);
assign(f,'cifra.out');rewrite(f);
writeln(f,x mod 10);
close(f);
end.