program cifra;
type tip1=1..30000;
var f,g:text;
    n,aux:longint;
    t:tip1;
    s,i:byte;
begin
assign(f,'cifra.in');reset(f);
assign(g,'cifra.out');rewrite(g);
readln(f,t);
while not eof(f) do
      begin
        readln(f,n);
        s:=0;
        for i:= 1 to n do
            begin
            aux:=i*i;
            s:=s+( aux mod 10);
            end;
        writeln(g,s mod 10);
      end;
close(f);
close(g);
end.