var   f,g:text;
n:integer;
p:longint;
function ult(x:longint):byte;
var j:byte;

begin
j:= x mod 10;
ult:=j;
end;
procedure suma(x:byte);
var s:byte;
begin
for i:=1 to p do
s:=s+i;
ult(s);
write(g,s);
end;

begin
assign(f,'cmmdc.in'); reset(f);
assign(g,'cmmdc.out'); rewrite(g);
read(f,n);
i:=0;
repeat
i:=i+1;
read(p);
suma(ult(p));
until i=n;
close(f);
close(g);
end.